class ParagonIE_Sodium_Compat in Automatic Updates 8

Hierarchy

• class \ParagonIE_Sodium_Compat

2 files declare their use of ParagonIE_Sodium_Compat

constants.php in vendor/paragonie/sodium_compat/lib/constants.php

sodium_compat.php in vendor/paragonie/sodium_compat/lib/sodium_compat.php

2 string references to 'ParagonIE_Sodium_Compat'

autoload.php in vendor/paragonie/sodium_compat/autoload.php

Compat.php in vendor/paragonie/sodium_compat/src/Compat.php

File

vendor/paragonie/sodium_compat/src/Compat.php, line 28

class ParagonIE_Sodium_Compat {

  /**
   * This parameter prevents the use of the PECL extension.
   * It should only be used for unit testing.
   *
   * @var bool
   */
  public static $disableFallbackForUnitTests = false;

  /**
   * Use fast multiplication rather than our constant-time multiplication
   * implementation. Can be enabled at runtime. Only enable this if you
   * are absolutely certain that there is no timing leak on your platform.
   *
   * @var bool
   */
  public static $fastMult = false;
  const LIBRARY_MAJOR_VERSION = 9;
  const LIBRARY_MINOR_VERSION = 1;
  const LIBRARY_VERSION_MAJOR = 9;
  const LIBRARY_VERSION_MINOR = 1;
  const VERSION_STRING = 'polyfill-1.0.8';

  // From libsodium
  const BASE64_VARIANT_ORIGINAL = 1;
  const BASE64_VARIANT_ORIGINAL_NO_PADDING = 3;
  const BASE64_VARIANT_URLSAFE = 5;
  const BASE64_VARIANT_URLSAFE_NO_PADDING = 7;
  const CRYPTO_AEAD_AES256GCM_KEYBYTES = 32;
  const CRYPTO_AEAD_AES256GCM_NSECBYTES = 0;
  const CRYPTO_AEAD_AES256GCM_NPUBBYTES = 12;
  const CRYPTO_AEAD_AES256GCM_ABYTES = 16;
  const CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES = 32;
  const CRYPTO_AEAD_CHACHA20POLY1305_NSECBYTES = 0;
  const CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES = 8;
  const CRYPTO_AEAD_CHACHA20POLY1305_ABYTES = 16;
  const CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES = 32;
  const CRYPTO_AEAD_CHACHA20POLY1305_IETF_NSECBYTES = 0;
  const CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES = 12;
  const CRYPTO_AEAD_CHACHA20POLY1305_IETF_ABYTES = 16;
  const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES = 32;
  const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NSECBYTES = 0;
  const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES = 24;
  const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES = 16;
  const CRYPTO_AUTH_BYTES = 32;
  const CRYPTO_AUTH_KEYBYTES = 32;
  const CRYPTO_BOX_SEALBYTES = 16;
  const CRYPTO_BOX_SECRETKEYBYTES = 32;
  const CRYPTO_BOX_PUBLICKEYBYTES = 32;
  const CRYPTO_BOX_KEYPAIRBYTES = 64;
  const CRYPTO_BOX_MACBYTES = 16;
  const CRYPTO_BOX_NONCEBYTES = 24;
  const CRYPTO_BOX_SEEDBYTES = 32;
  const CRYPTO_KDF_BYTES_MIN = 16;
  const CRYPTO_KDF_BYTES_MAX = 64;
  const CRYPTO_KDF_CONTEXTBYTES = 8;
  const CRYPTO_KDF_KEYBYTES = 32;
  const CRYPTO_KX_BYTES = 32;
  const CRYPTO_KX_PRIMITIVE = 'x25519blake2b';
  const CRYPTO_KX_SEEDBYTES = 32;
  const CRYPTO_KX_KEYPAIRBYTES = 64;
  const CRYPTO_KX_PUBLICKEYBYTES = 32;
  const CRYPTO_KX_SECRETKEYBYTES = 32;
  const CRYPTO_KX_SESSIONKEYBYTES = 32;
  const CRYPTO_GENERICHASH_BYTES = 32;
  const CRYPTO_GENERICHASH_BYTES_MIN = 16;
  const CRYPTO_GENERICHASH_BYTES_MAX = 64;
  const CRYPTO_GENERICHASH_KEYBYTES = 32;
  const CRYPTO_GENERICHASH_KEYBYTES_MIN = 16;
  const CRYPTO_GENERICHASH_KEYBYTES_MAX = 64;
  const CRYPTO_PWHASH_SALTBYTES = 16;
  const CRYPTO_PWHASH_STRPREFIX = '$argon2id$';
  const CRYPTO_PWHASH_ALG_ARGON2I13 = 1;
  const CRYPTO_PWHASH_ALG_ARGON2ID13 = 2;
  const CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE = 33554432;
  const CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE = 4;
  const CRYPTO_PWHASH_MEMLIMIT_MODERATE = 134217728;
  const CRYPTO_PWHASH_OPSLIMIT_MODERATE = 6;
  const CRYPTO_PWHASH_MEMLIMIT_SENSITIVE = 536870912;
  const CRYPTO_PWHASH_OPSLIMIT_SENSITIVE = 8;
  const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_SALTBYTES = 32;
  const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_STRPREFIX = '$7$';
  const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_INTERACTIVE = 534288;
  const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_INTERACTIVE = 16777216;
  const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_SENSITIVE = 33554432;
  const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_SENSITIVE = 1073741824;
  const CRYPTO_SCALARMULT_BYTES = 32;
  const CRYPTO_SCALARMULT_SCALARBYTES = 32;
  const CRYPTO_SHORTHASH_BYTES = 8;
  const CRYPTO_SHORTHASH_KEYBYTES = 16;
  const CRYPTO_SECRETBOX_KEYBYTES = 32;
  const CRYPTO_SECRETBOX_MACBYTES = 16;
  const CRYPTO_SECRETBOX_NONCEBYTES = 24;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_ABYTES = 17;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES = 24;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_KEYBYTES = 32;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_PUSH = 0;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_PULL = 1;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_REKEY = 2;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_FINAL = 3;
  const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_MESSAGEBYTES_MAX = 0x3fffffff80;
  const CRYPTO_SIGN_BYTES = 64;
  const CRYPTO_SIGN_SEEDBYTES = 32;
  const CRYPTO_SIGN_PUBLICKEYBYTES = 32;
  const CRYPTO_SIGN_SECRETKEYBYTES = 64;
  const CRYPTO_SIGN_KEYPAIRBYTES = 96;
  const CRYPTO_STREAM_KEYBYTES = 32;
  const CRYPTO_STREAM_NONCEBYTES = 24;

  /**
   * Add two numbers (little-endian unsigned), storing the value in the first
   * parameter.
   *
   * This mutates $val.
   *
   * @param string $val
   * @param string $addv
   * @return void
   * @throws SodiumException
   */
  public static function add(&$val, $addv) {
    $val_len = ParagonIE_Sodium_Core_Util::strlen($val);
    $addv_len = ParagonIE_Sodium_Core_Util::strlen($addv);
    if ($val_len !== $addv_len) {
      throw new SodiumException('values must have the same length');
    }
    $A = ParagonIE_Sodium_Core_Util::stringToIntArray($val);
    $B = ParagonIE_Sodium_Core_Util::stringToIntArray($addv);
    $c = 0;
    for ($i = 0; $i < $val_len; $i++) {
      $c += $A[$i] + $B[$i];
      $A[$i] = $c & 0xff;
      $c >>= 8;
    }
    $val = ParagonIE_Sodium_Core_Util::intArrayToString($A);
  }

  /**
   * @param string $encoded
   * @param int $variant
   * @param string $ignore
   * @return string
   * @throws SodiumException
   */
  public static function base642bin($encoded, $variant, $ignore = '') {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($encoded, 'string', 1);

    /** @var string $encoded */
    $encoded = (string) $encoded;
    if (ParagonIE_Sodium_Core_Util::strlen($encoded) === 0) {
      return '';
    }

    // Just strip before decoding
    if (!empty($ignore)) {
      $encoded = str_replace($ignore, '', $encoded);
    }
    try {
      switch ($variant) {
        case self::BASE64_VARIANT_ORIGINAL:
          return ParagonIE_Sodium_Core_Base64_Original::decode($encoded, true);
        case self::BASE64_VARIANT_ORIGINAL_NO_PADDING:
          return ParagonIE_Sodium_Core_Base64_Original::decode($encoded, false);
        case self::BASE64_VARIANT_URLSAFE:
          return ParagonIE_Sodium_Core_Base64_UrlSafe::decode($encoded, true);
        case self::BASE64_VARIANT_URLSAFE_NO_PADDING:
          return ParagonIE_Sodium_Core_Base64_UrlSafe::decode($encoded, false);
        default:
          throw new SodiumException('invalid base64 variant identifier');
      }
    } catch (Exception $ex) {
      if ($ex instanceof SodiumException) {
        throw $ex;
      }
      throw new SodiumException('invalid base64 string');
    }
  }

  /**
   * @param string $decoded
   * @param int $variant
   * @return string
   * @throws SodiumException
   */
  public static function bin2base64($decoded, $variant) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($decoded, 'string', 1);

    /** @var string $decoded */
    $decoded = (string) $decoded;
    if (ParagonIE_Sodium_Core_Util::strlen($decoded) === 0) {
      return '';
    }
    switch ($variant) {
      case self::BASE64_VARIANT_ORIGINAL:
        return ParagonIE_Sodium_Core_Base64_Original::encode($decoded);
      case self::BASE64_VARIANT_ORIGINAL_NO_PADDING:
        return ParagonIE_Sodium_Core_Base64_Original::encodeUnpadded($decoded);
      case self::BASE64_VARIANT_URLSAFE:
        return ParagonIE_Sodium_Core_Base64_UrlSafe::encode($decoded);
      case self::BASE64_VARIANT_URLSAFE_NO_PADDING:
        return ParagonIE_Sodium_Core_Base64_UrlSafe::encodeUnpadded($decoded);
      default:
        throw new SodiumException('invalid base64 variant identifier');
    }
  }

  /**
   * Cache-timing-safe implementation of bin2hex().
   *
   * @param string $string A string (probably raw binary)
   * @return string        A hexadecimal-encoded string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function bin2hex($string) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($string, 'string', 1);
    if (self::useNewSodiumAPI()) {
      return (string) sodium_bin2hex($string);
    }
    if (self::use_fallback('bin2hex')) {
      return (string) call_user_func('\\Sodium\\bin2hex', $string);
    }
    return ParagonIE_Sodium_Core_Util::bin2hex($string);
  }

  /**
   * Compare two strings, in constant-time.
   * Compared to memcmp(), compare() is more useful for sorting.
   *
   * @param string $left  The left operand; must be a string
   * @param string $right The right operand; must be a string
   * @return int          If < 0 if the left operand is less than the right
   *                      If = 0 if both strings are equal
   *                      If > 0 if the right operand is less than the left
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function compare($left, $right) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($left, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($right, 'string', 2);
    if (self::useNewSodiumAPI()) {
      return (int) sodium_compare($left, $right);
    }
    if (self::use_fallback('compare')) {
      return (int) call_user_func('\\Sodium\\compare', $left, $right);
    }
    return ParagonIE_Sodium_Core_Util::compare($left, $right);
  }

  /**
   * Is AES-256-GCM even available to use?
   *
   * @return bool
   * @psalm-suppress UndefinedFunction
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_aead_aes256gcm_is_available() {
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_aead_aes256gcm_is_available();
    }
    if (self::use_fallback('crypto_aead_aes256gcm_is_available')) {
      return call_user_func('\\Sodium\\crypto_aead_aes256gcm_is_available');
    }
    if (PHP_VERSION_ID < 70100) {

      // OpenSSL doesn't support AEAD before 7.1.0
      return false;
    }
    if (!is_callable('openssl_encrypt') || !is_callable('openssl_decrypt')) {

      // OpenSSL isn't installed
      return false;
    }
    return (bool) in_array('aes-256-gcm', openssl_get_cipher_methods());
  }

  /**
   * Authenticated Encryption with Associated Data: Decryption
   *
   * Algorithm:
   *     AES-256-GCM
   *
   * This mode uses a 64-bit random nonce with a 64-bit counter.
   * IETF mode uses a 96-bit random nonce with a 32-bit counter.
   *
   * @param string $ciphertext Encrypted message (with Poly1305 MAC appended)
   * @param string $assocData  Authenticated Associated Data (unencrypted)
   * @param string $nonce      Number to be used only Once; must be 8 bytes
   * @param string $key        Encryption key
   *
   * @return string|bool       The original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_aead_aes256gcm_decrypt($ciphertext = '', $assocData = '', $nonce = '', $key = '') {
    if (!self::crypto_aead_aes256gcm_is_available()) {
      throw new SodiumException('AES-256-GCM is not available');
    }
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AES256GCM_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_AES256GCM_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AES256GCM_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_AES256GCM_KEYBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_AES256GCM_ABYTES) {
      throw new SodiumException('Message must be at least CRYPTO_AEAD_AES256GCM_ABYTES long');
    }
    if (!is_callable('openssl_decrypt')) {
      throw new SodiumException('The OpenSSL extension is not installed, or openssl_decrypt() is not available');
    }

    /** @var string $ctext */
    $ctext = ParagonIE_Sodium_Core_Util::substr($ciphertext, 0, -self::CRYPTO_AEAD_AES256GCM_ABYTES);

    /** @var string $authTag */
    $authTag = ParagonIE_Sodium_Core_Util::substr($ciphertext, -self::CRYPTO_AEAD_AES256GCM_ABYTES, 16);
    return openssl_decrypt($ctext, 'aes-256-gcm', $key, OPENSSL_RAW_DATA, $nonce, $authTag, $assocData);
  }

  /**
   * Authenticated Encryption with Associated Data: Encryption
   *
   * Algorithm:
   *     AES-256-GCM
   *
   * @param string $plaintext Message to be encrypted
   * @param string $assocData Authenticated Associated Data (unencrypted)
   * @param string $nonce     Number to be used only Once; must be 8 bytes
   * @param string $key       Encryption key
   *
   * @return string           Ciphertext with a 16-byte GCM message
   *                          authentication code appended
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_aead_aes256gcm_encrypt($plaintext = '', $assocData = '', $nonce = '', $key = '') {
    if (!self::crypto_aead_aes256gcm_is_available()) {
      throw new SodiumException('AES-256-GCM is not available');
    }
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AES256GCM_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_AES256GCM_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AES256GCM_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_AES256GCM_KEYBYTES long');
    }
    if (!is_callable('openssl_encrypt')) {
      throw new SodiumException('The OpenSSL extension is not installed, or openssl_encrypt() is not available');
    }
    $authTag = '';
    $ciphertext = openssl_encrypt($plaintext, 'aes-256-gcm', $key, OPENSSL_RAW_DATA, $nonce, $authTag, $assocData);
    return $ciphertext . $authTag;
  }

  /**
   * Return a secure random key for use with the AES-256-GCM
   * symmetric AEAD interface.
   *
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_aead_aes256gcm_keygen() {
    return random_bytes(self::CRYPTO_AEAD_AES256GCM_KEYBYTES);
  }

  /**
   * Authenticated Encryption with Associated Data: Decryption
   *
   * Algorithm:
   *     ChaCha20-Poly1305
   *
   * This mode uses a 64-bit random nonce with a 64-bit counter.
   * IETF mode uses a 96-bit random nonce with a 32-bit counter.
   *
   * @param string $ciphertext Encrypted message (with Poly1305 MAC appended)
   * @param string $assocData  Authenticated Associated Data (unencrypted)
   * @param string $nonce      Number to be used only Once; must be 8 bytes
   * @param string $key        Encryption key
   *
   * @return string            The original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_aead_chacha20poly1305_decrypt($ciphertext = '', $assocData = '', $nonce = '', $key = '') {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_CHACHA20POLY1305_ABYTES) {
      throw new SodiumException('Message must be at least CRYPTO_AEAD_CHACHA20POLY1305_ABYTES long');
    }
    if (self::useNewSodiumAPI()) {

      /**
       * @psalm-suppress InvalidReturnStatement
       * @psalm-suppress FalsableReturnStatement
       */
      return sodium_crypto_aead_chacha20poly1305_decrypt($ciphertext, $assocData, $nonce, $key);
    }
    if (self::use_fallback('crypto_aead_chacha20poly1305_decrypt')) {
      return call_user_func('\\Sodium\\crypto_aead_chacha20poly1305_decrypt', $ciphertext, $assocData, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_decrypt($ciphertext, $assocData, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_decrypt($ciphertext, $assocData, $nonce, $key);
  }

  /**
   * Authenticated Encryption with Associated Data
   *
   * Algorithm:
   *     ChaCha20-Poly1305
   *
   * This mode uses a 64-bit random nonce with a 64-bit counter.
   * IETF mode uses a 96-bit random nonce with a 32-bit counter.
   *
   * @param string $plaintext Message to be encrypted
   * @param string $assocData Authenticated Associated Data (unencrypted)
   * @param string $nonce     Number to be used only Once; must be 8 bytes
   * @param string $key       Encryption key
   *
   * @return string           Ciphertext with a 16-byte Poly1305 message
   *                          authentication code appended
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_aead_chacha20poly1305_encrypt($plaintext = '', $assocData = '', $nonce = '', $key = '') {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_aead_chacha20poly1305_encrypt($plaintext, $assocData, $nonce, $key);
    }
    if (self::use_fallback('crypto_aead_chacha20poly1305_encrypt')) {
      return (string) call_user_func('\\Sodium\\crypto_aead_chacha20poly1305_encrypt', $plaintext, $assocData, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_encrypt($plaintext, $assocData, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_encrypt($plaintext, $assocData, $nonce, $key);
  }

  /**
   * Authenticated Encryption with Associated Data: Decryption
   *
   * Algorithm:
   *     ChaCha20-Poly1305
   *
   * IETF mode uses a 96-bit random nonce with a 32-bit counter.
   * Regular mode uses a 64-bit random nonce with a 64-bit counter.
   *
   * @param string $ciphertext Encrypted message (with Poly1305 MAC appended)
   * @param string $assocData  Authenticated Associated Data (unencrypted)
   * @param string $nonce      Number to be used only Once; must be 12 bytes
   * @param string $key        Encryption key
   *
   * @return string            The original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_aead_chacha20poly1305_ietf_decrypt($ciphertext = '', $assocData = '', $nonce = '', $key = '') {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_CHACHA20POLY1305_ABYTES) {
      throw new SodiumException('Message must be at least CRYPTO_AEAD_CHACHA20POLY1305_ABYTES long');
    }
    if (self::useNewSodiumAPI()) {

      /**
       * @psalm-suppress InvalidReturnStatement
       * @psalm-suppress FalsableReturnStatement
       */
      return sodium_crypto_aead_chacha20poly1305_ietf_decrypt($ciphertext, $assocData, $nonce, $key);
    }
    if (self::use_fallback('crypto_aead_chacha20poly1305_ietf_decrypt')) {
      return call_user_func('\\Sodium\\crypto_aead_chacha20poly1305_ietf_decrypt', $ciphertext, $assocData, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_ietf_decrypt($ciphertext, $assocData, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_ietf_decrypt($ciphertext, $assocData, $nonce, $key);
  }

  /**
   * Return a secure random key for use with the ChaCha20-Poly1305
   * symmetric AEAD interface.
   *
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_aead_chacha20poly1305_keygen() {
    return random_bytes(self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES);
  }

  /**
   * Authenticated Encryption with Associated Data
   *
   * Algorithm:
   *     ChaCha20-Poly1305
   *
   * IETF mode uses a 96-bit random nonce with a 32-bit counter.
   * Regular mode uses a 64-bit random nonce with a 64-bit counter.
   *
   * @param string $plaintext Message to be encrypted
   * @param string $assocData Authenticated Associated Data (unencrypted)
   * @param string $nonce Number to be used only Once; must be 8 bytes
   * @param string $key Encryption key
   *
   * @return string           Ciphertext with a 16-byte Poly1305 message
   *                          authentication code appended
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_aead_chacha20poly1305_ietf_encrypt($plaintext = '', $assocData = '', $nonce = '', $key = '') {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_aead_chacha20poly1305_ietf_encrypt($plaintext, $assocData, $nonce, $key);
    }
    if (self::use_fallback('crypto_aead_chacha20poly1305_ietf_encrypt')) {
      return (string) call_user_func('\\Sodium\\crypto_aead_chacha20poly1305_ietf_encrypt', $plaintext, $assocData, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_ietf_encrypt($plaintext, $assocData, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_ietf_encrypt($plaintext, $assocData, $nonce, $key);
  }

  /**
   * Return a secure random key for use with the ChaCha20-Poly1305
   * symmetric AEAD interface. (IETF version)
   *
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_aead_chacha20poly1305_ietf_keygen() {
    return random_bytes(self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES);
  }

  /**
   * Authenticated Encryption with Associated Data: Decryption
   *
   * Algorithm:
   *     XChaCha20-Poly1305
   *
   * This mode uses a 64-bit random nonce with a 64-bit counter.
   * IETF mode uses a 96-bit random nonce with a 32-bit counter.
   *
   * @param string $ciphertext   Encrypted message (with Poly1305 MAC appended)
   * @param string $assocData    Authenticated Associated Data (unencrypted)
   * @param string $nonce        Number to be used only Once; must be 8 bytes
   * @param string $key          Encryption key
   * @param bool   $dontFallback Don't fallback to ext/sodium
   *
   * @return string|bool         The original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_aead_xchacha20poly1305_ietf_decrypt($ciphertext = '', $assocData = '', $nonce = '', $key = '', $dontFallback = false) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES) {
      throw new SodiumException('Message must be at least CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES long');
    }
    if (self::useNewSodiumAPI() && !$dontFallback) {
      if (is_callable('sodium_crypto_aead_xchacha20poly1305_ietf_decrypt')) {
        return sodium_crypto_aead_xchacha20poly1305_ietf_decrypt($ciphertext, $assocData, $nonce, $key);
      }
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::aead_xchacha20poly1305_ietf_decrypt($ciphertext, $assocData, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::aead_xchacha20poly1305_ietf_decrypt($ciphertext, $assocData, $nonce, $key);
  }

  /**
   * Authenticated Encryption with Associated Data
   *
   * Algorithm:
   *     XChaCha20-Poly1305
   *
   * This mode uses a 64-bit random nonce with a 64-bit counter.
   * IETF mode uses a 96-bit random nonce with a 32-bit counter.
   *
   * @param string $plaintext    Message to be encrypted
   * @param string $assocData    Authenticated Associated Data (unencrypted)
   * @param string $nonce        Number to be used only Once; must be 8 bytes
   * @param string $key          Encryption key
   * @param bool   $dontFallback Don't fallback to ext/sodium
   *
   * @return string           Ciphertext with a 16-byte Poly1305 message
   *                          authentication code appended
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_aead_xchacha20poly1305_ietf_encrypt($plaintext = '', $assocData = '', $nonce = '', $key = '', $dontFallback = false) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES) {
      throw new SodiumException('Nonce must be CRYPTO_AEAD_XCHACHA20POLY1305_NPUBBYTES long');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES) {
      throw new SodiumException('Key must be CRYPTO_AEAD_XCHACHA20POLY1305_KEYBYTES long');
    }
    if (self::useNewSodiumAPI() && !$dontFallback) {
      if (is_callable('sodium_crypto_aead_xchacha20poly1305_ietf_encrypt')) {
        return sodium_crypto_aead_xchacha20poly1305_ietf_encrypt($plaintext, $assocData, $nonce, $key);
      }
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::aead_xchacha20poly1305_ietf_encrypt($plaintext, $assocData, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::aead_xchacha20poly1305_ietf_encrypt($plaintext, $assocData, $nonce, $key);
  }

  /**
   * Return a secure random key for use with the XChaCha20-Poly1305
   * symmetric AEAD interface.
   *
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_aead_xchacha20poly1305_ietf_keygen() {
    return random_bytes(self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES);
  }

  /**
   * Authenticate a message. Uses symmetric-key cryptography.
   *
   * Algorithm:
   *     HMAC-SHA512-256. Which is HMAC-SHA-512 truncated to 256 bits.
   *     Not to be confused with HMAC-SHA-512/256 which would use the
   *     SHA-512/256 hash function (uses different initial parameters
   *     but still truncates to 256 bits to sidestep length-extension
   *     attacks).
   *
   * @param string $message Message to be authenticated
   * @param string $key Symmetric authentication key
   * @return string         Message authentication code
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_auth($message, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AUTH_KEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_AUTH_KEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_auth($message, $key);
    }
    if (self::use_fallback('crypto_auth')) {
      return (string) call_user_func('\\Sodium\\crypto_auth', $message, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::auth($message, $key);
    }
    return ParagonIE_Sodium_Crypto::auth($message, $key);
  }

  /**
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_auth_keygen() {
    return random_bytes(self::CRYPTO_AUTH_KEYBYTES);
  }

  /**
   * Verify the MAC of a message previously authenticated with crypto_auth.
   *
   * @param string $mac Message authentication code
   * @param string $message Message whose authenticity you are attempting to
   *                        verify (with a given MAC and key)
   * @param string $key Symmetric authentication key
   * @return bool           TRUE if authenticated, FALSE otherwise
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_auth_verify($mac, $message, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($mac, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($mac) !== self::CRYPTO_AUTH_BYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_AUTH_BYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AUTH_KEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_AUTH_KEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (bool) sodium_crypto_auth_verify($mac, $message, $key);
    }
    if (self::use_fallback('crypto_auth_verify')) {
      return (bool) call_user_func('\\Sodium\\crypto_auth_verify', $mac, $message, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::auth_verify($mac, $message, $key);
    }
    return ParagonIE_Sodium_Crypto::auth_verify($mac, $message, $key);
  }

  /**
   * Authenticated asymmetric-key encryption. Both the sender and recipient
   * may decrypt messages.
   *
   * Algorithm: X25519-XSalsa20-Poly1305.
   *     X25519: Elliptic-Curve Diffie Hellman over Curve25519.
   *     XSalsa20: Extended-nonce variant of salsa20.
   *     Poyl1305: Polynomial MAC for one-time message authentication.
   *
   * @param string $plaintext The message to be encrypted
   * @param string $nonce A Number to only be used Once; must be 24 bytes
   * @param string $keypair Your secret key and your recipient's public key
   * @return string           Ciphertext with 16-byte Poly1305 MAC
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_box($plaintext, $nonce, $keypair) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_BOX_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_BOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_BOX_KEYPAIRBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box($plaintext, $nonce, $keypair);
    }
    if (self::use_fallback('crypto_box')) {
      return (string) call_user_func('\\Sodium\\crypto_box', $plaintext, $nonce, $keypair);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box($plaintext, $nonce, $keypair);
    }
    return ParagonIE_Sodium_Crypto::box($plaintext, $nonce, $keypair);
  }

  /**
   * Anonymous public-key encryption. Only the recipient may decrypt messages.
   *
   * Algorithm: X25519-XSalsa20-Poly1305, as with crypto_box.
   *     The sender's X25519 keypair is ephemeral.
   *     Nonce is generated from the BLAKE2b hash of both public keys.
   *
   * This provides ciphertext integrity.
   *
   * @param string $plaintext Message to be sealed
   * @param string $publicKey Your recipient's public key
   * @return string           Sealed message that only your recipient can
   *                          decrypt
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_box_seal($plaintext, $publicKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box_seal($plaintext, $publicKey);
    }
    if (self::use_fallback('crypto_box_seal')) {
      return (string) call_user_func('\\Sodium\\crypto_box_seal', $plaintext, $publicKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_seal($plaintext, $publicKey);
    }
    return ParagonIE_Sodium_Crypto::box_seal($plaintext, $publicKey);
  }

  /**
   * Opens a message encrypted with crypto_box_seal(). Requires
   * the recipient's keypair (sk || pk) to decrypt successfully.
   *
   * This validates ciphertext integrity.
   *
   * @param string $ciphertext Sealed message to be opened
   * @param string $keypair    Your crypto_box keypair
   * @return string            The original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_box_seal_open($ciphertext, $keypair) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_BOX_KEYPAIRBYTES long.');
    }
    if (self::useNewSodiumAPI()) {

      /**
       * @psalm-suppress InvalidReturnStatement
       * @psalm-suppress FalsableReturnStatement
       */
      return sodium_crypto_box_seal_open($ciphertext, $keypair);
    }
    if (self::use_fallback('crypto_box_seal_open')) {
      return call_user_func('\\Sodium\\crypto_box_seal_open', $ciphertext, $keypair);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_seal_open($ciphertext, $keypair);
    }
    return ParagonIE_Sodium_Crypto::box_seal_open($ciphertext, $keypair);
  }

  /**
   * Generate a new random X25519 keypair.
   *
   * @return string A 64-byte string; the first 32 are your secret key, while
   *                the last 32 are your public key. crypto_box_secretkey()
   *                and crypto_box_publickey() exist to separate them so you
   *                don't accidentally get them mixed up!
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_box_keypair() {
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box_keypair();
    }
    if (self::use_fallback('crypto_box_keypair')) {
      return (string) call_user_func('\\Sodium\\crypto_box_keypair');
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_keypair();
    }
    return ParagonIE_Sodium_Crypto::box_keypair();
  }

  /**
   * Combine two keys into a keypair for use in library methods that expect
   * a keypair. This doesn't necessarily have to be the same person's keys.
   *
   * @param string $secretKey Secret key
   * @param string $publicKey Public key
   * @return string    Keypair
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_box_keypair_from_secretkey_and_publickey($secretKey, $publicKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box_keypair_from_secretkey_and_publickey($secretKey, $publicKey);
    }
    if (self::use_fallback('crypto_box_keypair_from_secretkey_and_publickey')) {
      return (string) call_user_func('\\Sodium\\crypto_box_keypair_from_secretkey_and_publickey', $secretKey, $publicKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_keypair_from_secretkey_and_publickey($secretKey, $publicKey);
    }
    return ParagonIE_Sodium_Crypto::box_keypair_from_secretkey_and_publickey($secretKey, $publicKey);
  }

  /**
   * Decrypt a message previously encrypted with crypto_box().
   *
   * @param string $ciphertext Encrypted message
   * @param string $nonce      Number to only be used Once; must be 24 bytes
   * @param string $keypair    Your secret key and the sender's public key
   * @return string            The original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_box_open($ciphertext, $nonce, $keypair) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_BOX_MACBYTES) {
      throw new SodiumException('Argument 1 must be at least CRYPTO_BOX_MACBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_BOX_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_BOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_BOX_KEYPAIRBYTES long.');
    }
    if (self::useNewSodiumAPI()) {

      /**
       * @psalm-suppress InvalidReturnStatement
       * @psalm-suppress FalsableReturnStatement
       */
      return sodium_crypto_box_open($ciphertext, $nonce, $keypair);
    }
    if (self::use_fallback('crypto_box_open')) {
      return call_user_func('\\Sodium\\crypto_box_open', $ciphertext, $nonce, $keypair);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_open($ciphertext, $nonce, $keypair);
    }
    return ParagonIE_Sodium_Crypto::box_open($ciphertext, $nonce, $keypair);
  }

  /**
   * Extract the public key from a crypto_box keypair.
   *
   * @param string $keypair Keypair containing secret and public key
   * @return string         Your crypto_box public key
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_box_publickey($keypair) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_BOX_KEYPAIRBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box_publickey($keypair);
    }
    if (self::use_fallback('crypto_box_publickey')) {
      return (string) call_user_func('\\Sodium\\crypto_box_publickey', $keypair);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_publickey($keypair);
    }
    return ParagonIE_Sodium_Crypto::box_publickey($keypair);
  }

  /**
   * Calculate the X25519 public key from a given X25519 secret key.
   *
   * @param string $secretKey Any X25519 secret key
   * @return string           The corresponding X25519 public key
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_box_publickey_from_secretkey($secretKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box_publickey_from_secretkey($secretKey);
    }
    if (self::use_fallback('crypto_box_publickey_from_secretkey')) {
      return (string) call_user_func('\\Sodium\\crypto_box_publickey_from_secretkey', $secretKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_publickey_from_secretkey($secretKey);
    }
    return ParagonIE_Sodium_Crypto::box_publickey_from_secretkey($secretKey);
  }

  /**
   * Extract the secret key from a crypto_box keypair.
   *
   * @param string $keypair
   * @return string         Your crypto_box secret key
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_box_secretkey($keypair) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_BOX_KEYPAIRBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box_secretkey($keypair);
    }
    if (self::use_fallback('crypto_box_secretkey')) {
      return (string) call_user_func('\\Sodium\\crypto_box_secretkey', $keypair);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_secretkey($keypair);
    }
    return ParagonIE_Sodium_Crypto::box_secretkey($keypair);
  }

  /**
   * Generate an X25519 keypair from a seed.
   *
   * @param string $seed
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress UndefinedFunction
   */
  public static function crypto_box_seed_keypair($seed) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($seed, 'string', 1);
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_box_seed_keypair($seed);
    }
    if (self::use_fallback('crypto_box_seed_keypair')) {
      return (string) call_user_func('\\Sodium\\crypto_box_seed_keypair', $seed);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::box_seed_keypair($seed);
    }
    return ParagonIE_Sodium_Crypto::box_seed_keypair($seed);
  }

  /**
   * Calculates a BLAKE2b hash, with an optional key.
   *
   * @param string      $message The message to be hashed
   * @param string|null $key     If specified, must be a string between 16
   *                             and 64 bytes long
   * @param int         $length  Output length in bytes; must be between 16
   *                             and 64 (default = 32)
   * @return string              Raw binary
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_generichash($message, $key = '', $length = self::CRYPTO_GENERICHASH_BYTES) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
    if (is_null($key)) {
      $key = '';
    }
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 3);

    /* Input validation: */
    if (!empty($key)) {
      if (ParagonIE_Sodium_Core_Util::strlen($key) < self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
        throw new SodiumException('Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.');
      }
      if (ParagonIE_Sodium_Core_Util::strlen($key) > self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
        throw new SodiumException('Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.');
      }
    }
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_generichash($message, $key, $length);
    }
    if (self::use_fallback('crypto_generichash')) {
      return (string) call_user_func('\\Sodium\\crypto_generichash', $message, $key, $length);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::generichash($message, $key, $length);
    }
    return ParagonIE_Sodium_Crypto::generichash($message, $key, $length);
  }

  /**
   * Get the final BLAKE2b hash output for a given context.
   *
   * @param string $ctx BLAKE2 hashing context. Generated by crypto_generichash_init().
   * @param int $length Hash output size.
   * @return string     Final BLAKE2b hash.
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress ReferenceConstraintViolation
   * @psalm-suppress ConflictingReferenceConstraint
   */
  public static function crypto_generichash_final(&$ctx, $length = self::CRYPTO_GENERICHASH_BYTES) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ctx, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 2);
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_generichash_final($ctx, $length);
    }
    if (self::use_fallback('crypto_generichash_final')) {
      $func = '\\Sodium\\crypto_generichash_final';
      return (string) $func($ctx, $length);
    }
    if ($length < 1) {
      try {
        self::memzero($ctx);
      } catch (SodiumException $ex) {
        unset($ctx);
      }
      return '';
    }
    if (PHP_INT_SIZE === 4) {
      $result = ParagonIE_Sodium_Crypto32::generichash_final($ctx, $length);
    }
    else {
      $result = ParagonIE_Sodium_Crypto::generichash_final($ctx, $length);
    }
    try {
      self::memzero($ctx);
    } catch (SodiumException $ex) {
      unset($ctx);
    }
    return $result;
  }

  /**
   * Initialize a BLAKE2b hashing context, for use in a streaming interface.
   *
   * @param string|null $key If specified must be a string between 16 and 64 bytes
   * @param int $length      The size of the desired hash output
   * @return string          A BLAKE2 hashing context, encoded as a string
   *                         (To be 100% compatible with ext/libsodium)
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_generichash_init($key = '', $length = self::CRYPTO_GENERICHASH_BYTES) {

    /* Type checks: */
    if (is_null($key)) {
      $key = '';
    }
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 2);

    /* Input validation: */
    if (!empty($key)) {
      if (ParagonIE_Sodium_Core_Util::strlen($key) < self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
        throw new SodiumException('Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.');
      }
      if (ParagonIE_Sodium_Core_Util::strlen($key) > self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
        throw new SodiumException('Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.');
      }
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_generichash_init($key, $length);
    }
    if (self::use_fallback('crypto_generichash_init')) {
      return (string) call_user_func('\\Sodium\\crypto_generichash_init', $key, $length);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::generichash_init($key, $length);
    }
    return ParagonIE_Sodium_Crypto::generichash_init($key, $length);
  }

  /**
   * Initialize a BLAKE2b hashing context, for use in a streaming interface.
   *
   * @param string|null $key If specified must be a string between 16 and 64 bytes
   * @param int $length      The size of the desired hash output
   * @param string $salt     Salt (up to 16 bytes)
   * @param string $personal Personalization string (up to 16 bytes)
   * @return string          A BLAKE2 hashing context, encoded as a string
   *                         (To be 100% compatible with ext/libsodium)
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_generichash_init_salt_personal($key = '', $length = self::CRYPTO_GENERICHASH_BYTES, $salt = '', $personal = '') {

    /* Type checks: */
    if (is_null($key)) {
      $key = '';
    }
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($salt, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($personal, 'string', 4);
    $salt = str_pad($salt, 16, "\0", STR_PAD_RIGHT);
    $personal = str_pad($personal, 16, "\0", STR_PAD_RIGHT);

    /* Input validation: */
    if (!empty($key)) {

      /*
      if (ParagonIE_Sodium_Core_Util::strlen($key) < self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
          throw new SodiumException('Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.');
      }
      */
      if (ParagonIE_Sodium_Core_Util::strlen($key) > self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
        throw new SodiumException('Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.');
      }
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::generichash_init_salt_personal($key, $length, $salt, $personal);
    }
    return ParagonIE_Sodium_Crypto::generichash_init_salt_personal($key, $length, $salt, $personal);
  }

  /**
   * Update a BLAKE2b hashing context with additional data.
   *
   * @param string $ctx    BLAKE2 hashing context. Generated by crypto_generichash_init().
   *                       $ctx is passed by reference and gets updated in-place.
   * @param-out string $ctx
   * @param string $message The message to append to the existing hash state.
   * @return void
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress ReferenceConstraintViolation
   */
  public static function crypto_generichash_update(&$ctx, $message) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ctx, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 2);
    if (self::useNewSodiumAPI()) {
      sodium_crypto_generichash_update($ctx, $message);
      return;
    }
    if (self::use_fallback('crypto_generichash_update')) {
      $func = '\\Sodium\\crypto_generichash_update';
      $func($ctx, $message);
      return;
    }
    if (PHP_INT_SIZE === 4) {
      $ctx = ParagonIE_Sodium_Crypto32::generichash_update($ctx, $message);
    }
    else {
      $ctx = ParagonIE_Sodium_Crypto::generichash_update($ctx, $message);
    }
  }

  /**
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_generichash_keygen() {
    return random_bytes(self::CRYPTO_GENERICHASH_KEYBYTES);
  }

  /**
   * @param int $subkey_len
   * @param int $subkey_id
   * @param string $context
   * @param string $key
   * @return string
   * @throws SodiumException
   */
  public static function crypto_kdf_derive_from_key($subkey_len, $subkey_id, $context, $key) {
    ParagonIE_Sodium_Core_Util::declareScalarType($subkey_len, 'int', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($subkey_id, 'int', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($context, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);
    $subkey_id = (int) $subkey_id;
    $subkey_len = (int) $subkey_len;
    $context = (string) $context;
    $key = (string) $key;
    if ($subkey_len < self::CRYPTO_KDF_BYTES_MIN) {
      throw new SodiumException('subkey cannot be smaller than SODIUM_CRYPTO_KDF_BYTES_MIN');
    }
    if ($subkey_len > self::CRYPTO_KDF_BYTES_MAX) {
      throw new SodiumException('subkey cannot be larger than SODIUM_CRYPTO_KDF_BYTES_MAX');
    }
    if ($subkey_id < 0) {
      throw new SodiumException('subkey_id cannot be negative');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($context) !== self::CRYPTO_KDF_CONTEXTBYTES) {
      throw new SodiumException('context should be SODIUM_CRYPTO_KDF_CONTEXTBYTES bytes');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_KDF_KEYBYTES) {
      throw new SodiumException('key should be SODIUM_CRYPTO_KDF_KEYBYTES bytes');
    }
    $salt = ParagonIE_Sodium_Core_Util::store64_le($subkey_id);
    $state = self::crypto_generichash_init_salt_personal($key, $subkey_len, $salt, $context);
    return self::crypto_generichash_final($state, $subkey_len);
  }

  /**
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_kdf_keygen() {
    return random_bytes(self::CRYPTO_KDF_KEYBYTES);
  }

  /**
   * Perform a key exchange, between a designated client and a server.
   *
   * Typically, you would designate one machine to be the client and the
   * other to be the server. The first two keys are what you'd expect for
   * scalarmult() below, but the latter two public keys don't swap places.
   *
   * | ALICE                          | BOB                                 |
   * | Client                         | Server                              |
   * |--------------------------------|-------------------------------------|
   * | shared = crypto_kx(            | shared = crypto_kx(                 |
   * |     alice_sk,                  |     bob_sk,                         | <- contextual
   * |     bob_pk,                    |     alice_pk,                       | <- contextual
   * |     alice_pk,                  |     alice_pk,                       | <----- static
   * |     bob_pk                     |     bob_pk                          | <----- static
   * | )                              | )                                   |
   *
   * They are used along with the scalarmult product to generate a 256-bit
   * BLAKE2b hash unique to the client and server keys.
   *
   * @param string $my_secret
   * @param string $their_public
   * @param string $client_public
   * @param string $server_public
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_kx($my_secret, $their_public, $client_public, $server_public) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($my_secret, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($their_public, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($client_public, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($server_public, 'string', 4);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($my_secret) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($their_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($client_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($server_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 4 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      if (is_callable('sodium_crypto_kx')) {
        return (string) sodium_crypto_kx($my_secret, $their_public, $client_public, $server_public);
      }
    }
    if (self::use_fallback('crypto_kx')) {
      return (string) call_user_func('\\Sodium\\crypto_kx', $my_secret, $their_public, $client_public, $server_public);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::keyExchange($my_secret, $their_public, $client_public, $server_public);
    }
    return ParagonIE_Sodium_Crypto::keyExchange($my_secret, $their_public, $client_public, $server_public);
  }

  /**
   * @param string $seed
   * @return string
   * @throws SodiumException
   */
  public static function crypto_kx_seed_keypair($seed) {
    ParagonIE_Sodium_Core_Util::declareScalarType($seed, 'string', 1);
    $seed = (string) $seed;
    if (ParagonIE_Sodium_Core_Util::strlen($seed) !== self::CRYPTO_KX_SEEDBYTES) {
      throw new SodiumException('seed must be SODIUM_CRYPTO_KX_SEEDBYTES bytes');
    }
    $sk = self::crypto_generichash($seed, '', self::CRYPTO_KX_SECRETKEYBYTES);
    $pk = self::crypto_scalarmult_base($sk);
    return $sk . $pk;
  }

  /**
   * @return string
   * @throws Exception
   */
  public static function crypto_kx_keypair() {
    $sk = self::randombytes_buf(self::CRYPTO_KX_SECRETKEYBYTES);
    $pk = self::crypto_scalarmult_base($sk);
    return $sk . $pk;
  }

  /**
   * @param string $keypair
   * @param string $serverPublicKey
   * @return array{0: string, 1: string}
   * @throws SodiumException
   */
  public static function crypto_kx_client_session_keys($keypair, $serverPublicKey) {
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($serverPublicKey, 'string', 2);
    $keypair = (string) $keypair;
    $serverPublicKey = (string) $serverPublicKey;
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_KX_KEYPAIRBYTES) {
      throw new SodiumException('keypair should be SODIUM_CRYPTO_KX_KEYPAIRBYTES bytes');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($serverPublicKey) !== self::CRYPTO_KX_PUBLICKEYBYTES) {
      throw new SodiumException('public keys must be SODIUM_CRYPTO_KX_PUBLICKEYBYTES bytes');
    }
    $sk = self::crypto_kx_secretkey($keypair);
    $pk = self::crypto_kx_publickey($keypair);
    $h = self::crypto_generichash_init(null, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
    self::crypto_generichash_update($h, self::crypto_scalarmult($sk, $serverPublicKey));
    self::crypto_generichash_update($h, $pk);
    self::crypto_generichash_update($h, $serverPublicKey);
    $sessionKeys = self::crypto_generichash_final($h, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
    return array(
      ParagonIE_Sodium_Core_Util::substr($sessionKeys, 0, self::CRYPTO_KX_SESSIONKEYBYTES),
      ParagonIE_Sodium_Core_Util::substr($sessionKeys, self::CRYPTO_KX_SESSIONKEYBYTES, self::CRYPTO_KX_SESSIONKEYBYTES),
    );
  }

  /**
   * @param string $keypair
   * @param string $clientPublicKey
   * @return array{0: string, 1: string}
   * @throws SodiumException
   */
  public static function crypto_kx_server_session_keys($keypair, $clientPublicKey) {
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($clientPublicKey, 'string', 2);
    $keypair = (string) $keypair;
    $clientPublicKey = (string) $clientPublicKey;
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_KX_KEYPAIRBYTES) {
      throw new SodiumException('keypair should be SODIUM_CRYPTO_KX_KEYPAIRBYTES bytes');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($clientPublicKey) !== self::CRYPTO_KX_PUBLICKEYBYTES) {
      throw new SodiumException('public keys must be SODIUM_CRYPTO_KX_PUBLICKEYBYTES bytes');
    }
    $sk = self::crypto_kx_secretkey($keypair);
    $pk = self::crypto_kx_publickey($keypair);
    $h = self::crypto_generichash_init(null, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
    self::crypto_generichash_update($h, self::crypto_scalarmult($sk, $clientPublicKey));
    self::crypto_generichash_update($h, $clientPublicKey);
    self::crypto_generichash_update($h, $pk);
    $sessionKeys = self::crypto_generichash_final($h, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
    return array(
      ParagonIE_Sodium_Core_Util::substr($sessionKeys, self::CRYPTO_KX_SESSIONKEYBYTES, self::CRYPTO_KX_SESSIONKEYBYTES),
      ParagonIE_Sodium_Core_Util::substr($sessionKeys, 0, self::CRYPTO_KX_SESSIONKEYBYTES),
    );
  }

  /**
   * @param string $kp
   * @return string
   * @throws SodiumException
   */
  public static function crypto_kx_secretkey($kp) {
    return ParagonIE_Sodium_Core_Util::substr($kp, 0, self::CRYPTO_KX_SECRETKEYBYTES);
  }

  /**
   * @param string $kp
   * @return string
   * @throws SodiumException
   */
  public static function crypto_kx_publickey($kp) {
    return ParagonIE_Sodium_Core_Util::substr($kp, self::CRYPTO_KX_SECRETKEYBYTES, self::CRYPTO_KX_PUBLICKEYBYTES);
  }

  /**
   * @param int $outlen
   * @param string $passwd
   * @param string $salt
   * @param int $opslimit
   * @param int $memlimit
   * @param int|null $alg
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_pwhash($outlen, $passwd, $salt, $opslimit, $memlimit, $alg = null) {
    ParagonIE_Sodium_Core_Util::declareScalarType($outlen, 'int', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($salt, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 4);
    ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 5);
    if (self::useNewSodiumAPI()) {
      if (!is_null($alg)) {
        ParagonIE_Sodium_Core_Util::declareScalarType($alg, 'int', 6);
        return sodium_crypto_pwhash($outlen, $passwd, $salt, $opslimit, $memlimit, $alg);
      }
      return sodium_crypto_pwhash($outlen, $passwd, $salt, $opslimit, $memlimit);
    }
    if (self::use_fallback('crypto_pwhash')) {
      return (string) call_user_func('\\Sodium\\crypto_pwhash', $outlen, $passwd, $salt, $opslimit, $memlimit);
    }

    // This is the best we can do.
    throw new SodiumException('This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP');
  }

  /**
   * !Exclusive to sodium_compat!
   *
   * This returns TRUE if the native crypto_pwhash API is available by libsodium.
   * This returns FALSE if only sodium_compat is available.
   *
   * @return bool
   */
  public static function crypto_pwhash_is_available() {
    if (self::useNewSodiumAPI()) {
      return true;
    }
    if (self::use_fallback('crypto_pwhash')) {
      return true;
    }
    return false;
  }

  /**
   * @param string $passwd
   * @param int $opslimit
   * @param int $memlimit
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_pwhash_str($passwd, $opslimit, $memlimit) {
    ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 3);
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_pwhash_str($passwd, $opslimit, $memlimit);
    }
    if (self::use_fallback('crypto_pwhash_str')) {
      return (string) call_user_func('\\Sodium\\crypto_pwhash_str', $passwd, $opslimit, $memlimit);
    }

    // This is the best we can do.
    throw new SodiumException('This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP');
  }

  /**
   * Do we need to rehash this password?
   *
   * @param string $hash
   * @param int $opslimit
   * @param int $memlimit
   * @return bool
   * @throws SodiumException
   */
  public static function crypto_pwhash_str_needs_rehash($hash, $opslimit, $memlimit) {
    ParagonIE_Sodium_Core_Util::declareScalarType($hash, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 3);

    // Just grab the first 4 pieces.
    $pieces = explode('$', (string) $hash);
    $prefix = implode('$', array_slice($pieces, 0, 4));

    // Rebuild the expected header.

    /** @var int $ops */
    $ops = (int) $opslimit;

    /** @var int $mem */
    $mem = (int) $memlimit >> 10;
    $encoded = self::CRYPTO_PWHASH_STRPREFIX . 'v=19$m=' . $mem . ',t=' . $ops . ',p=1';

    // Do they match? If so, we don't need to rehash, so return false.
    return !ParagonIE_Sodium_Core_Util::hashEquals($encoded, $prefix);
  }

  /**
   * @param string $passwd
   * @param string $hash
   * @return bool
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_pwhash_str_verify($passwd, $hash) {
    ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($hash, 'string', 2);
    if (self::useNewSodiumAPI()) {
      return (bool) sodium_crypto_pwhash_str_verify($passwd, $hash);
    }
    if (self::use_fallback('crypto_pwhash_str_verify')) {
      return (bool) call_user_func('\\Sodium\\crypto_pwhash_str_verify', $passwd, $hash);
    }

    // This is the best we can do.
    throw new SodiumException('This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP');
  }

  /**
   * @param int $outlen
   * @param string $passwd
   * @param string $salt
   * @param int $opslimit
   * @param int $memlimit
   * @return string
   * @throws SodiumException
   * @throws TypeError
   */
  public static function crypto_pwhash_scryptsalsa208sha256($outlen, $passwd, $salt, $opslimit, $memlimit) {
    ParagonIE_Sodium_Core_Util::declareScalarType($outlen, 'int', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($salt, 'string', 3);
    ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 4);
    ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 5);
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_pwhash_scryptsalsa208sha256((int) $outlen, (string) $passwd, (string) $salt, (int) $opslimit, (int) $memlimit);
    }
    if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256')) {
      return (string) call_user_func('\\Sodium\\crypto_pwhash_scryptsalsa208sha256', (int) $outlen, (string) $passwd, (string) $salt, (int) $opslimit, (int) $memlimit);
    }

    // This is the best we can do.
    throw new SodiumException('This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP');
  }

  /**
   * !Exclusive to sodium_compat!
   *
   * This returns TRUE if the native crypto_pwhash API is available by libsodium.
   * This returns FALSE if only sodium_compat is available.
   *
   * @return bool
   */
  public static function crypto_pwhash_scryptsalsa208sha256_is_available() {
    if (self::useNewSodiumAPI()) {
      return true;
    }
    if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256')) {
      return true;
    }
    return false;
  }

  /**
   * @param string $passwd
   * @param int $opslimit
   * @param int $memlimit
   * @return string
   * @throws SodiumException
   * @throws TypeError
   */
  public static function crypto_pwhash_scryptsalsa208sha256_str($passwd, $opslimit, $memlimit) {
    ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 3);
    if (self::useNewSodiumAPI()) {
      return (string) sodium_crypto_pwhash_scryptsalsa208sha256_str((string) $passwd, (int) $opslimit, (int) $memlimit);
    }
    if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256_str')) {
      return (string) call_user_func('\\Sodium\\crypto_pwhash_scryptsalsa208sha256_str', (string) $passwd, (int) $opslimit, (int) $memlimit);
    }

    // This is the best we can do.
    throw new SodiumException('This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP');
  }

  /**
   * @param string $passwd
   * @param string $hash
   * @return bool
   * @throws SodiumException
   * @throws TypeError
   */
  public static function crypto_pwhash_scryptsalsa208sha256_str_verify($passwd, $hash) {
    ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($hash, 'string', 2);
    if (self::useNewSodiumAPI()) {
      return (bool) sodium_crypto_pwhash_scryptsalsa208sha256_str_verify((string) $passwd, (string) $hash);
    }
    if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256_str_verify')) {
      return (bool) call_user_func('\\Sodium\\crypto_pwhash_scryptsalsa208sha256_str_verify', (string) $passwd, (string) $hash);
    }

    // This is the best we can do.
    throw new SodiumException('This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP');
  }

  /**
   * Calculate the shared secret between your secret key and your
   * recipient's public key.
   *
   * Algorithm: X25519 (ECDH over Curve25519)
   *
   * @param string $secretKey
   * @param string $publicKey
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_scalarmult($secretKey, $publicKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_scalarmult($secretKey, $publicKey);
    }
    if (self::use_fallback('crypto_scalarmult')) {
      return (string) call_user_func('\\Sodium\\crypto_scalarmult', $secretKey, $publicKey);
    }

    /* Output validation: Forbid all-zero keys */
    if (ParagonIE_Sodium_Core_Util::hashEquals($secretKey, str_repeat("\0", self::CRYPTO_BOX_SECRETKEYBYTES))) {
      throw new SodiumException('Zero secret key is not allowed');
    }
    if (ParagonIE_Sodium_Core_Util::hashEquals($publicKey, str_repeat("\0", self::CRYPTO_BOX_PUBLICKEYBYTES))) {
      throw new SodiumException('Zero public key is not allowed');
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::scalarmult($secretKey, $publicKey);
    }
    return ParagonIE_Sodium_Crypto::scalarmult($secretKey, $publicKey);
  }

  /**
   * Calculate an X25519 public key from an X25519 secret key.
   *
   * @param string $secretKey
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress TooFewArguments
   * @psalm-suppress MixedArgument
   */
  public static function crypto_scalarmult_base($secretKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_scalarmult_base($secretKey);
    }
    if (self::use_fallback('crypto_scalarmult_base')) {
      return (string) call_user_func('\\Sodium\\crypto_scalarmult_base', $secretKey);
    }
    if (ParagonIE_Sodium_Core_Util::hashEquals($secretKey, str_repeat("\0", self::CRYPTO_BOX_SECRETKEYBYTES))) {
      throw new SodiumException('Zero secret key is not allowed');
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::scalarmult_base($secretKey);
    }
    return ParagonIE_Sodium_Crypto::scalarmult_base($secretKey);
  }

  /**
   * Authenticated symmetric-key encryption.
   *
   * Algorithm: XSalsa20-Poly1305
   *
   * @param string $plaintext The message you're encrypting
   * @param string $nonce A Number to be used Once; must be 24 bytes
   * @param string $key Symmetric encryption key
   * @return string           Ciphertext with Poly1305 MAC
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_secretbox($plaintext, $nonce, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_secretbox($plaintext, $nonce, $key);
    }
    if (self::use_fallback('crypto_secretbox')) {
      return (string) call_user_func('\\Sodium\\crypto_secretbox', $plaintext, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretbox($plaintext, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::secretbox($plaintext, $nonce, $key);
  }

  /**
   * Decrypts a message previously encrypted with crypto_secretbox().
   *
   * @param string $ciphertext Ciphertext with Poly1305 MAC
   * @param string $nonce      A Number to be used Once; must be 24 bytes
   * @param string $key        Symmetric encryption key
   * @return string            Original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_secretbox_open($ciphertext, $nonce, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {

      /**
       * @psalm-suppress InvalidReturnStatement
       * @psalm-suppress FalsableReturnStatement
       */
      return sodium_crypto_secretbox_open($ciphertext, $nonce, $key);
    }
    if (self::use_fallback('crypto_secretbox_open')) {
      return call_user_func('\\Sodium\\crypto_secretbox_open', $ciphertext, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretbox_open($ciphertext, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::secretbox_open($ciphertext, $nonce, $key);
  }

  /**
   * Return a secure random key for use with crypto_secretbox
   *
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_secretbox_keygen() {
    return random_bytes(self::CRYPTO_SECRETBOX_KEYBYTES);
  }

  /**
   * Authenticated symmetric-key encryption.
   *
   * Algorithm: XChaCha20-Poly1305
   *
   * @param string $plaintext The message you're encrypting
   * @param string $nonce     A Number to be used Once; must be 24 bytes
   * @param string $key       Symmetric encryption key
   * @return string           Ciphertext with Poly1305 MAC
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_secretbox_xchacha20poly1305($plaintext, $nonce, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretbox_xchacha20poly1305($plaintext, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::secretbox_xchacha20poly1305($plaintext, $nonce, $key);
  }

  /**
   * Decrypts a message previously encrypted with crypto_secretbox_xchacha20poly1305().
   *
   * @param string $ciphertext Ciphertext with Poly1305 MAC
   * @param string $nonce      A Number to be used Once; must be 24 bytes
   * @param string $key        Symmetric encryption key
   * @return string            Original plaintext message
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_secretbox_xchacha20poly1305_open($ciphertext, $nonce, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretbox_xchacha20poly1305_open($ciphertext, $nonce, $key);
    }
    return ParagonIE_Sodium_Crypto::secretbox_xchacha20poly1305_open($ciphertext, $nonce, $key);
  }

  /**
   * @param string $key
   * @return array<int, string> Returns a state and a header.
   * @throws Exception
   * @throws SodiumException
   */
  public static function crypto_secretstream_xchacha20poly1305_init_push($key) {
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_init_push($key);
    }
    return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_init_push($key);
  }

  /**
   * @param string $header
   * @param string $key
   * @return string Returns a state.
   * @throws Exception
   */
  public static function crypto_secretstream_xchacha20poly1305_init_pull($header, $key) {
    if (ParagonIE_Sodium_Core_Util::strlen($header) < self::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES) {
      throw new SodiumException('header size should be SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES bytes');
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_init_pull($key, $header);
    }
    return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_init_pull($key, $header);
  }

  /**
   * @param string $state
   * @param string $msg
   * @param string $aad
   * @param int $tag
   * @return string
   * @throws SodiumException
   */
  public static function crypto_secretstream_xchacha20poly1305_push(&$state, $msg, $aad = '', $tag = 0) {
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_push($state, $msg, $aad, $tag);
    }
    return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_push($state, $msg, $aad, $tag);
  }

  /**
   * @param string $state
   * @param string $msg
   * @param string $aad
   * @return bool|array{0: string, 1: int}
   * @throws SodiumException
   */
  public static function crypto_secretstream_xchacha20poly1305_pull(&$state, $msg, $aad = '') {
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_pull($state, $msg, $aad);
    }
    return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_pull($state, $msg, $aad);
  }

  /**
   * @return string
   * @throws Exception
   */
  public static function crypto_secretstream_xchacha20poly1305_keygen() {
    return random_bytes(self::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_KEYBYTES);
  }

  /**
   * @param string $state
   * @return void
   * @throws SodiumException
   */
  public static function crypto_secretstream_xchacha20poly1305_rekey(&$state) {
    if (PHP_INT_SIZE === 4) {
      ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_rekey($state);
    }
    else {
      ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_rekey($state);
    }
  }

  /**
   * Calculates a SipHash-2-4 hash of a message for a given key.
   *
   * @param string $message Input message
   * @param string $key SipHash-2-4 key
   * @return string         Hash
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_shorthash($message, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SHORTHASH_KEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SHORTHASH_KEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_shorthash($message, $key);
    }
    if (self::use_fallback('crypto_shorthash')) {
      return (string) call_user_func('\\Sodium\\crypto_shorthash', $message, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_SipHash::sipHash24($message, $key);
    }
    return ParagonIE_Sodium_Core_SipHash::sipHash24($message, $key);
  }

  /**
   * Return a secure random key for use with crypto_shorthash
   *
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_shorthash_keygen() {
    return random_bytes(self::CRYPTO_SHORTHASH_KEYBYTES);
  }

  /**
   * Returns a signed message. You probably want crypto_sign_detached()
   * instead, which only returns the signature.
   *
   * Algorithm: Ed25519 (EdDSA over Curve25519)
   *
   * @param string $message Message to be signed.
   * @param string $secretKey Secret signing key.
   * @return string           Signed message (signature is prefixed).
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_sign($message, $secretKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SIGN_SECRETKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign($message, $secretKey);
    }
    if (self::use_fallback('crypto_sign')) {
      return (string) call_user_func('\\Sodium\\crypto_sign', $message, $secretKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::sign($message, $secretKey);
    }
    return ParagonIE_Sodium_Crypto::sign($message, $secretKey);
  }

  /**
   * Validates a signed message then returns the message.
   *
   * @param string $signedMessage A signed message
   * @param string $publicKey A public key
   * @return string               The original message (if the signature is
   *                              valid for this public key)
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress MixedReturnStatement
   */
  public static function crypto_sign_open($signedMessage, $publicKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($signedMessage, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($signedMessage) < self::CRYPTO_SIGN_BYTES) {
      throw new SodiumException('Argument 1 must be at least CRYPTO_SIGN_BYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SIGN_PUBLICKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {

      /**
       * @psalm-suppress InvalidReturnStatement
       * @psalm-suppress FalsableReturnStatement
       */
      return sodium_crypto_sign_open($signedMessage, $publicKey);
    }
    if (self::use_fallback('crypto_sign_open')) {
      return call_user_func('\\Sodium\\crypto_sign_open', $signedMessage, $publicKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::sign_open($signedMessage, $publicKey);
    }
    return ParagonIE_Sodium_Crypto::sign_open($signedMessage, $publicKey);
  }

  /**
   * Generate a new random Ed25519 keypair.
   *
   * @return string
   * @throws SodiumException
   * @throws TypeError
   */
  public static function crypto_sign_keypair() {
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_keypair();
    }
    if (self::use_fallback('crypto_sign_keypair')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_keypair');
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_Ed25519::keypair();
    }
    return ParagonIE_Sodium_Core_Ed25519::keypair();
  }

  /**
   * @param string $sk
   * @param string $pk
   * @return string
   * @throws SodiumException
   */
  public static function crypto_sign_keypair_from_secretkey_and_publickey($sk, $pk) {
    ParagonIE_Sodium_Core_Util::declareScalarType($sk, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($pk, 'string', 1);
    $sk = (string) $sk;
    $pk = (string) $pk;
    if (ParagonIE_Sodium_Core_Util::strlen($sk) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
      throw new SodiumException('secretkey should be SODIUM_CRYPTO_SIGN_SECRETKEYBYTES bytes');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($pk) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
      throw new SodiumException('publickey should be SODIUM_CRYPTO_SIGN_PUBLICKEYBYTES bytes');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_keypair_from_secretkey_and_publickey($sk, $pk);
    }
    return $sk . $pk;
  }

  /**
   * Generate an Ed25519 keypair from a seed.
   *
   * @param string $seed Input seed
   * @return string      Keypair
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_seed_keypair($seed) {
    ParagonIE_Sodium_Core_Util::declareScalarType($seed, 'string', 1);
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_seed_keypair($seed);
    }
    if (self::use_fallback('crypto_sign_keypair')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_seed_keypair', $seed);
    }
    $publicKey = '';
    $secretKey = '';
    if (PHP_INT_SIZE === 4) {
      ParagonIE_Sodium_Core32_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
    }
    else {
      ParagonIE_Sodium_Core_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
    }
    return $secretKey . $publicKey;
  }

  /**
   * Extract an Ed25519 public key from an Ed25519 keypair.
   *
   * @param string $keypair Keypair
   * @return string         Public key
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_publickey($keypair) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_SIGN_KEYPAIRBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_SIGN_KEYPAIRBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_publickey($keypair);
    }
    if (self::use_fallback('crypto_sign_publickey')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_publickey', $keypair);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_Ed25519::publickey($keypair);
    }
    return ParagonIE_Sodium_Core_Ed25519::publickey($keypair);
  }

  /**
   * Calculate an Ed25519 public key from an Ed25519 secret key.
   *
   * @param string $secretKey Your Ed25519 secret key
   * @return string           The corresponding Ed25519 public key
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_publickey_from_secretkey($secretKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_SIGN_SECRETKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_publickey_from_secretkey($secretKey);
    }
    if (self::use_fallback('crypto_sign_publickey_from_secretkey')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_publickey_from_secretkey', $secretKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_Ed25519::publickey_from_secretkey($secretKey);
    }
    return ParagonIE_Sodium_Core_Ed25519::publickey_from_secretkey($secretKey);
  }

  /**
   * Extract an Ed25519 secret key from an Ed25519 keypair.
   *
   * @param string $keypair Keypair
   * @return string         Secret key
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_secretkey($keypair) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_SIGN_KEYPAIRBYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_SIGN_KEYPAIRBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_secretkey($keypair);
    }
    if (self::use_fallback('crypto_sign_secretkey')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_secretkey', $keypair);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_Ed25519::secretkey($keypair);
    }
    return ParagonIE_Sodium_Core_Ed25519::secretkey($keypair);
  }

  /**
   * Calculate the Ed25519 signature of a message and return ONLY the signature.
   *
   * Algorithm: Ed25519 (EdDSA over Curve25519)
   *
   * @param string $message Message to be signed
   * @param string $secretKey Secret signing key
   * @return string           Digital signature
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_detached($message, $secretKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 2);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SIGN_SECRETKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_detached($message, $secretKey);
    }
    if (self::use_fallback('crypto_sign_detached')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_detached', $message, $secretKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::sign_detached($message, $secretKey);
    }
    return ParagonIE_Sodium_Crypto::sign_detached($message, $secretKey);
  }

  /**
   * Verify the Ed25519 signature of a message.
   *
   * @param string $signature Digital sginature
   * @param string $message Message to be verified
   * @param string $publicKey Public key
   * @return bool             TRUE if this signature is good for this public key;
   *                          FALSE otherwise
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_verify_detached($signature, $message, $publicKey) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($signature, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($signature) !== self::CRYPTO_SIGN_BYTES) {
      throw new SodiumException('Argument 1 must be CRYPTO_SIGN_BYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_SIGN_PUBLICKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_sign_verify_detached($signature, $message, $publicKey);
    }
    if (self::use_fallback('crypto_sign_verify_detached')) {
      return (bool) call_user_func('\\Sodium\\crypto_sign_verify_detached', $signature, $message, $publicKey);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Crypto32::sign_verify_detached($signature, $message, $publicKey);
    }
    return ParagonIE_Sodium_Crypto::sign_verify_detached($signature, $message, $publicKey);
  }

  /**
   * Convert an Ed25519 public key to a Curve25519 public key
   *
   * @param string $pk
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_ed25519_pk_to_curve25519($pk) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($pk, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($pk) < self::CRYPTO_SIGN_PUBLICKEYBYTES) {
      throw new SodiumException('Argument 1 must be at least CRYPTO_SIGN_PUBLICKEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      if (is_callable('crypto_sign_ed25519_pk_to_curve25519')) {
        return (string) sodium_crypto_sign_ed25519_pk_to_curve25519($pk);
      }
    }
    if (self::use_fallback('crypto_sign_ed25519_pk_to_curve25519')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_ed25519_pk_to_curve25519', $pk);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_Ed25519::pk_to_curve25519($pk);
    }
    return ParagonIE_Sodium_Core_Ed25519::pk_to_curve25519($pk);
  }

  /**
   * Convert an Ed25519 secret key to a Curve25519 secret key
   *
   * @param string $sk
   * @return string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_sign_ed25519_sk_to_curve25519($sk) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($sk, 'string', 1);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($sk) < self::CRYPTO_SIGN_SEEDBYTES) {
      throw new SodiumException('Argument 1 must be at least CRYPTO_SIGN_SEEDBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      if (is_callable('crypto_sign_ed25519_sk_to_curve25519')) {
        return sodium_crypto_sign_ed25519_sk_to_curve25519($sk);
      }
    }
    if (self::use_fallback('crypto_sign_ed25519_sk_to_curve25519')) {
      return (string) call_user_func('\\Sodium\\crypto_sign_ed25519_sk_to_curve25519', $sk);
    }
    $h = hash('sha512', ParagonIE_Sodium_Core_Util::substr($sk, 0, 32), true);
    $h[0] = ParagonIE_Sodium_Core_Util::intToChr(ParagonIE_Sodium_Core_Util::chrToInt($h[0]) & 248);
    $h[31] = ParagonIE_Sodium_Core_Util::intToChr(ParagonIE_Sodium_Core_Util::chrToInt($h[31]) & 127 | 64);
    return ParagonIE_Sodium_Core_Util::substr($h, 0, 32);
  }

  /**
   * Expand a key and nonce into a keystream of pseudorandom bytes.
   *
   * @param int $len Number of bytes desired
   * @param string $nonce Number to be used Once; must be 24 bytes
   * @param string $key XSalsa20 key
   * @return string       Pseudorandom stream that can be XORed with messages
   *                      to provide encryption (but not authentication; see
   *                      Poly1305 or crypto_auth() for that, which is not
   *                      optional for security)
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_stream($len, $nonce, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($len, 'int', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_KEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_STREAM_KEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_stream($len, $nonce, $key);
    }
    if (self::use_fallback('crypto_stream')) {
      return (string) call_user_func('\\Sodium\\crypto_stream', $len, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_XSalsa20::xsalsa20($len, $nonce, $key);
    }
    return ParagonIE_Sodium_Core_XSalsa20::xsalsa20($len, $nonce, $key);
  }

  /**
   * DANGER! UNAUTHENTICATED ENCRYPTION!
   *
   * Unless you are following expert advice, do not used this feature.
   *
   * Algorithm: XSalsa20
   *
   * This DOES NOT provide ciphertext integrity.
   *
   * @param string $message Plaintext message
   * @param string $nonce Number to be used Once; must be 24 bytes
   * @param string $key Encryption key
   * @return string         Encrypted text which is vulnerable to chosen-
   *                        ciphertext attacks unless you implement some
   *                        other mitigation to the ciphertext (i.e.
   *                        Encrypt then MAC)
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function crypto_stream_xor($message, $nonce, $key) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
    ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

    /* Input validation: */
    if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_NONCEBYTES) {
      throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
    }
    if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_KEYBYTES) {
      throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
    }
    if (self::useNewSodiumAPI()) {
      return sodium_crypto_stream_xor($message, $nonce, $key);
    }
    if (self::use_fallback('crypto_stream_xor')) {
      return (string) call_user_func('\\Sodium\\crypto_stream_xor', $message, $nonce, $key);
    }
    if (PHP_INT_SIZE === 4) {
      return ParagonIE_Sodium_Core32_XSalsa20::xsalsa20_xor($message, $nonce, $key);
    }
    return ParagonIE_Sodium_Core_XSalsa20::xsalsa20_xor($message, $nonce, $key);
  }

  /**
   * Return a secure random key for use with crypto_stream
   *
   * @return string
   * @throws Exception
   * @throws Error
   */
  public static function crypto_stream_keygen() {
    return random_bytes(self::CRYPTO_STREAM_KEYBYTES);
  }

  /**
   * Cache-timing-safe implementation of hex2bin().
   *
   * @param string $string Hexadecimal string
   * @return string        Raw binary string
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress TooFewArguments
   * @psalm-suppress MixedArgument
   */
  public static function hex2bin($string) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($string, 'string', 1);
    if (self::useNewSodiumAPI()) {
      if (is_callable('sodium_hex2bin')) {
        return (string) sodium_hex2bin($string);
      }
    }
    if (self::use_fallback('hex2bin')) {
      return (string) call_user_func('\\Sodium\\hex2bin', $string);
    }
    return ParagonIE_Sodium_Core_Util::hex2bin($string);
  }

  /**
   * Increase a string (little endian)
   *
   * @param string $var
   *
   * @return void
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function increment(&$var) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($var, 'string', 1);
    if (self::useNewSodiumAPI()) {
      sodium_increment($var);
      return;
    }
    if (self::use_fallback('increment')) {
      $func = '\\Sodium\\increment';
      $func($var);
      return;
    }
    $len = ParagonIE_Sodium_Core_Util::strlen($var);
    $c = 1;
    $copy = '';
    for ($i = 0; $i < $len; ++$i) {
      $c += ParagonIE_Sodium_Core_Util::chrToInt(ParagonIE_Sodium_Core_Util::substr($var, $i, 1));
      $copy .= ParagonIE_Sodium_Core_Util::intToChr($c);
      $c >>= 8;
    }
    $var = $copy;
  }

  /**
   * The equivalent to the libsodium minor version we aim to be compatible
   * with (sans pwhash and memzero).
   *
   * @return int
   */
  public static function library_version_major() {
    if (self::useNewSodiumAPI() && defined('SODIUM_LIBRARY_MAJOR_VERSION')) {
      return SODIUM_LIBRARY_MAJOR_VERSION;
    }
    if (self::use_fallback('library_version_major')) {

      /** @psalm-suppress UndefinedFunction */
      return (int) call_user_func('\\Sodium\\library_version_major');
    }
    return self::LIBRARY_VERSION_MAJOR;
  }

  /**
   * The equivalent to the libsodium minor version we aim to be compatible
   * with (sans pwhash and memzero).
   *
   * @return int
   */
  public static function library_version_minor() {
    if (self::useNewSodiumAPI() && defined('SODIUM_LIBRARY_MINOR_VERSION')) {
      return SODIUM_LIBRARY_MINOR_VERSION;
    }
    if (self::use_fallback('library_version_minor')) {

      /** @psalm-suppress UndefinedFunction */
      return (int) call_user_func('\\Sodium\\library_version_minor');
    }
    return self::LIBRARY_VERSION_MINOR;
  }

  /**
   * Compare two strings.
   *
   * @param string $left
   * @param string $right
   * @return int
   * @throws SodiumException
   * @throws TypeError
   * @psalm-suppress MixedArgument
   */
  public static function memcmp($left, $right) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($left, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($right, 'string', 2);
    if (self::useNewSodiumAPI()) {
      return sodium_memcmp($left, $right);
    }
    if (self::use_fallback('memcmp')) {
      return (int) call_user_func('\\Sodium\\memcmp', $left, $right);
    }

    /** @var string $left */

    /** @var string $right */
    return ParagonIE_Sodium_Core_Util::memcmp($left, $right);
  }

  /**
   * It's actually not possible to zero memory buffers in PHP. You need the
   * native library for that.
   *
   * @param string|null $var
   * @param-out string|null $var
   *
   * @return void
   * @throws SodiumException (Unless libsodium is installed)
   * @throws TypeError
   * @psalm-suppress TooFewArguments
   */
  public static function memzero(&$var) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($var, 'string', 1);
    if (self::useNewSodiumAPI()) {

      /** @psalm-suppress MixedArgument */
      sodium_memzero($var);
      return;
    }
    if (self::use_fallback('memzero')) {
      $func = '\\Sodium\\memzero';
      $func($var);
      if ($var === null) {
        return;
      }
    }

    // This is the best we can do.
    throw new SodiumException('This is not implemented in sodium_compat, as it is not possible to securely wipe memory from PHP. ' . 'To fix this error, make sure libsodium is installed and the PHP extension is enabled.');
  }

  /**
   * @param string $unpadded
   * @param int $blockSize
   * @param bool $dontFallback
   * @return string
   * @throws SodiumException
   */
  public static function pad($unpadded, $blockSize, $dontFallback = false) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($unpadded, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($blockSize, 'int', 2);
    $unpadded = (string) $unpadded;
    $blockSize = (int) $blockSize;
    if (self::useNewSodiumAPI() && !$dontFallback) {
      return (string) sodium_pad($unpadded, $blockSize);
    }
    if ($blockSize <= 0) {
      throw new SodiumException('block size cannot be less than 1');
    }
    $unpadded_len = ParagonIE_Sodium_Core_Util::strlen($unpadded);
    $xpadlen = $blockSize - 1;
    if (($blockSize & $blockSize - 1) === 0) {
      $xpadlen -= $unpadded_len & $blockSize - 1;
    }
    else {
      $xpadlen -= $unpadded_len % $blockSize;
    }
    $xpadded_len = $unpadded_len + $xpadlen;
    $padded = str_repeat("\0", $xpadded_len - 1);
    if ($unpadded_len > 0) {
      $st = 1;
      $i = 0;
      $k = $unpadded_len;
      for ($j = 0; $j <= $xpadded_len; ++$j) {
        $i = (int) $i;
        $k = (int) $k;
        $st = (int) $st;
        if ($j >= $unpadded_len) {
          $padded[$j] = "\0";
        }
        else {
          $padded[$j] = $unpadded[$j];
        }

        /** @var int $k */
        $k -= $st;
        $st = (int) ~(($k >> 48 | $k >> 32 | $k >> 16 | $k) - 1 >> 16) & 1;
        $i += $st;
      }
    }
    $mask = 0;
    $tail = $xpadded_len;
    for ($i = 0; $i < $blockSize; ++$i) {

      # barrier_mask = (unsigned char)

      #     (((i ^ xpadlen) - 1U) >> ((sizeof(size_t) - 1U) * CHAR_BIT));
      $barrier_mask = ($i ^ $xpadlen) - 1 >> (PHP_INT_SIZE << 3) - 1;

      # tail[-i] = (tail[-i] & mask) | (0x80 & barrier_mask);
      $padded[$tail - $i] = ParagonIE_Sodium_Core_Util::intToChr(ParagonIE_Sodium_Core_Util::chrToInt($padded[$tail - $i]) & $mask | 0x80 & $barrier_mask);

      # mask |= barrier_mask;
      $mask |= $barrier_mask;
    }
    return $padded;
  }

  /**
   * @param string $padded
   * @param int $blockSize
   * @param bool $dontFallback
   * @return string
   * @throws SodiumException
   */
  public static function unpad($padded, $blockSize, $dontFallback = false) {

    /* Type checks: */
    ParagonIE_Sodium_Core_Util::declareScalarType($padded, 'string', 1);
    ParagonIE_Sodium_Core_Util::declareScalarType($blockSize, 'int', 2);
    $padded = (string) $padded;
    $blockSize = (int) $blockSize;
    if (self::useNewSodiumAPI() && !$dontFallback) {
      return (string) sodium_unpad($padded, $blockSize);
    }
    if ($blockSize <= 0) {
      throw new SodiumException('block size cannot be less than 1');
    }
    $padded_len = ParagonIE_Sodium_Core_Util::strlen($padded);
    if ($padded_len < $blockSize) {
      throw new SodiumException('invalid padding');
    }

    # tail = &padded[padded_len - 1U];
    $tail = $padded_len - 1;
    $acc = 0;
    $valid = 0;
    $pad_len = 0;
    $found = 0;
    for ($i = 0; $i < $blockSize; ++$i) {

      # c = tail[-i];
      $c = ParagonIE_Sodium_Core_Util::chrToInt($padded[$tail - $i]);

      # is_barrier =

      #     (( (acc - 1U) & (pad_len - 1U) & ((c ^ 0x80) - 1U) ) >> 8) & 1U;
      $is_barrier = ($acc - 1 & $pad_len - 1 & ($c ^ 80) - 1) >> 7 & 1;
      $is_barrier &= ~$found;
      $found |= $is_barrier;

      # acc |= c;
      $acc |= $c;

      # pad_len |= i & (1U + ~is_barrier);
      $pad_len |= $i & 1 + ~$is_barrier;

      # valid |= (unsigned char) is_barrier;
      $valid |= $is_barrier & 0xff;
    }

    # unpadded_len = padded_len - 1U - pad_len;
    $unpadded_len = $padded_len - 1 - $pad_len;
    if ($valid !== 1) {
      throw new SodiumException('invalid padding');
    }
    return ParagonIE_Sodium_Core_Util::substr($padded, 0, $unpadded_len);
  }

  /**
   * Will sodium_compat run fast on the current hardware and PHP configuration?
   *
   * @return bool
   */
  public static function polyfill_is_fast() {
    if (extension_loaded('sodium')) {
      return true;
    }
    if (extension_loaded('libsodium')) {
      return true;
    }
    return PHP_INT_SIZE === 8;
  }

  /**
   * Generate a string of bytes from the kernel's CSPRNG.
   * Proudly uses /dev/urandom (if getrandom(2) is not available).
   *
   * @param int $numBytes
   * @return string
   * @throws Exception
   * @throws TypeError
   */
  public static function randombytes_buf($numBytes) {

    /* Type checks: */
    if (!is_int($numBytes)) {
      if (is_numeric($numBytes)) {
        $numBytes = (int) $numBytes;
      }
      else {
        throw new TypeError('Argument 1 must be an integer, ' . gettype($numBytes) . ' given.');
      }
    }
    if (self::use_fallback('randombytes_buf')) {
      return (string) call_user_func('\\Sodium\\randombytes_buf', $numBytes);
    }
    return random_bytes($numBytes);
  }

  /**
   * Generate an integer between 0 and $range (non-inclusive).
   *
   * @param int $range
   * @return int
   * @throws Exception
   * @throws Error
   * @throws TypeError
   */
  public static function randombytes_uniform($range) {

    /* Type checks: */
    if (!is_int($range)) {
      if (is_numeric($range)) {
        $range = (int) $range;
      }
      else {
        throw new TypeError('Argument 1 must be an integer, ' . gettype($range) . ' given.');
      }
    }
    if (self::use_fallback('randombytes_uniform')) {
      return (int) call_user_func('\\Sodium\\randombytes_uniform', $range);
    }
    return random_int(0, $range - 1);
  }

  /**
   * Generate a random 16-bit integer.
   *
   * @return int
   * @throws Exception
   * @throws Error
   * @throws TypeError
   */
  public static function randombytes_random16() {
    if (self::use_fallback('randombytes_random16')) {
      return (int) call_user_func('\\Sodium\\randombytes_random16');
    }
    return random_int(0, 65535);
  }

  /**
   * Runtime testing method for 32-bit platforms.
   *
   * Usage: If runtime_speed_test() returns FALSE, then our 32-bit
   *        implementation is to slow to use safely without risking timeouts.
   *        If this happens, install sodium from PECL to get acceptable
   *        performance.
   *
   * @param int $iterations Number of multiplications to attempt
   * @param int $maxTimeout Milliseconds
   * @return bool           TRUE if we're fast enough, FALSE is not
   * @throws SodiumException
   */
  public static function runtime_speed_test($iterations, $maxTimeout) {
    if (self::polyfill_is_fast()) {
      return true;
    }

    /** @var float $end */
    $end = 0.0;

    /** @var float $start */
    $start = microtime(true);

    /** @var ParagonIE_Sodium_Core32_Int64 $a */
    $a = ParagonIE_Sodium_Core32_Int64::fromInt(random_int(3, 1 << 16));
    for ($i = 0; $i < $iterations; ++$i) {

      /** @var ParagonIE_Sodium_Core32_Int64 $b */
      $b = ParagonIE_Sodium_Core32_Int64::fromInt(random_int(3, 1 << 16));
      $a
        ->mulInt64($b);
    }

    /** @var float $end */
    $end = microtime(true);

    /** @var int $diff */
    $diff = (int) ceil(($end - $start) * 1000);
    return $diff < $maxTimeout;
  }

  /**
   * This emulates libsodium's version_string() function, except ours is
   * prefixed with 'polyfill-'.
   *
   * @return string
   * @psalm-suppress MixedInferredReturnType
   * @psalm-suppress UndefinedFunction
   */
  public static function version_string() {
    if (self::useNewSodiumAPI()) {
      return (string) sodium_version_string();
    }
    if (self::use_fallback('version_string')) {
      return (string) call_user_func('\\Sodium\\version_string');
    }
    return (string) self::VERSION_STRING;
  }

  /**
   * Should we use the libsodium core function instead?
   * This is always a good idea, if it's available. (Unless we're in the
   * middle of running our unit test suite.)
   *
   * If ext/libsodium is available, use it. Return TRUE.
   * Otherwise, we have to use the code provided herein. Return FALSE.
   *
   * @param string $sodium_func_name
   *
   * @return bool
   */
  protected static function use_fallback($sodium_func_name = '') {
    static $res = null;
    if ($res === null) {
      $res = extension_loaded('libsodium') && PHP_VERSION_ID >= 50300;
    }
    if ($res === false) {

      // No libsodium installed
      return false;
    }
    if (self::$disableFallbackForUnitTests) {

      // Don't fallback. Use the PHP implementation.
      return false;
    }
    if (!empty($sodium_func_name)) {
      return is_callable('\\Sodium\\' . $sodium_func_name);
    }
    return true;
  }

  /**
   * Libsodium as implemented in PHP 7.2
   * and/or ext/sodium (via PECL)
   *
   * @ref https://wiki.php.net/rfc/libsodium
   * @return bool
   */
  protected static function useNewSodiumAPI() {
    static $res = null;
    if ($res === null) {
      $res = PHP_VERSION_ID >= 70000 && extension_loaded('sodium');
    }
    if (self::$disableFallbackForUnitTests) {

      // Don't fallback. Use the PHP implementation.
      return false;
    }
    return (bool) $res;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
ParagonIE_Sodium_Compat::$disableFallbackForUnitTests	public static	property	This parameter prevents the use of the PECL extension. It should only be used for unit testing.
ParagonIE_Sodium_Compat::$fastMult	public static	property	Use fast multiplication rather than our constant-time multiplication implementation. Can be enabled at runtime. Only enable this if you are absolutely certain that there is no timing leak on your platform.
ParagonIE_Sodium_Compat::add	public static	function	Add two numbers (little-endian unsigned), storing the value in the first parameter.
ParagonIE_Sodium_Compat::base642bin	public static	function
ParagonIE_Sodium_Compat::BASE64_VARIANT_ORIGINAL		constant
ParagonIE_Sodium_Compat::BASE64_VARIANT_ORIGINAL_NO_PADDING		constant
ParagonIE_Sodium_Compat::BASE64_VARIANT_URLSAFE		constant
ParagonIE_Sodium_Compat::BASE64_VARIANT_URLSAFE_NO_PADDING		constant
ParagonIE_Sodium_Compat::bin2base64	public static	function
ParagonIE_Sodium_Compat::bin2hex	public static	function	Cache-timing-safe implementation of bin2hex().
ParagonIE_Sodium_Compat::compare	public static	function	Compare two strings, in constant-time. Compared to memcmp(), compare() is more useful for sorting.
ParagonIE_Sodium_Compat::CRYPTO_AEAD_AES256GCM_ABYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_aes256gcm_decrypt	public static	function	Authenticated Encryption with Associated Data: Decryption
ParagonIE_Sodium_Compat::crypto_aead_aes256gcm_encrypt	public static	function	Authenticated Encryption with Associated Data: Encryption
ParagonIE_Sodium_Compat::crypto_aead_aes256gcm_is_available	public static	function	Is AES-256-GCM even available to use?
ParagonIE_Sodium_Compat::CRYPTO_AEAD_AES256GCM_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_aes256gcm_keygen	public static	function	Return a secure random key for use with the AES-256-GCM symmetric AEAD interface.
ParagonIE_Sodium_Compat::CRYPTO_AEAD_AES256GCM_NPUBBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AEAD_AES256GCM_NSECBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_ABYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_chacha20poly1305_decrypt	public static	function	Authenticated Encryption with Associated Data: Decryption
ParagonIE_Sodium_Compat::crypto_aead_chacha20poly1305_encrypt	public static	function	Authenticated Encryption with Associated Data
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_IETF_ABYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_chacha20poly1305_ietf_decrypt	public static	function	Authenticated Encryption with Associated Data: Decryption
ParagonIE_Sodium_Compat::crypto_aead_chacha20poly1305_ietf_encrypt	public static	function	Authenticated Encryption with Associated Data
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_chacha20poly1305_ietf_keygen	public static	function	Return a secure random key for use with the ChaCha20-Poly1305 symmetric AEAD interface. (IETF version)
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NSECBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_chacha20poly1305_keygen	public static	function	Return a secure random key for use with the ChaCha20-Poly1305 symmetric AEAD interface.
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AEAD_CHACHA20POLY1305_NSECBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_xchacha20poly1305_ietf_decrypt	public static	function	Authenticated Encryption with Associated Data: Decryption
ParagonIE_Sodium_Compat::crypto_aead_xchacha20poly1305_ietf_encrypt	public static	function	Authenticated Encryption with Associated Data
ParagonIE_Sodium_Compat::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_aead_xchacha20poly1305_ietf_keygen	public static	function	Return a secure random key for use with the XChaCha20-Poly1305 symmetric AEAD interface.
ParagonIE_Sodium_Compat::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NSECBYTES		constant
ParagonIE_Sodium_Compat::crypto_auth	public static	function	Authenticate a message. Uses symmetric-key cryptography.
ParagonIE_Sodium_Compat::CRYPTO_AUTH_BYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_AUTH_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_auth_keygen	public static	function
ParagonIE_Sodium_Compat::crypto_auth_verify	public static	function	Verify the MAC of a message previously authenticated with crypto_auth.
ParagonIE_Sodium_Compat::crypto_box	public static	function	Authenticated asymmetric-key encryption. Both the sender and recipient may decrypt messages.
ParagonIE_Sodium_Compat::crypto_box_keypair	public static	function	Generate a new random X25519 keypair.
ParagonIE_Sodium_Compat::CRYPTO_BOX_KEYPAIRBYTES		constant
ParagonIE_Sodium_Compat::crypto_box_keypair_from_secretkey_and_publickey	public static	function	Combine two keys into a keypair for use in library methods that expect a keypair. This doesn't necessarily have to be the same person's keys.
ParagonIE_Sodium_Compat::CRYPTO_BOX_MACBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_BOX_NONCEBYTES		constant
ParagonIE_Sodium_Compat::crypto_box_open	public static	function	Decrypt a message previously encrypted with crypto_box().
ParagonIE_Sodium_Compat::crypto_box_publickey	public static	function	Extract the public key from a crypto_box keypair.
ParagonIE_Sodium_Compat::CRYPTO_BOX_PUBLICKEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_box_publickey_from_secretkey	public static	function	Calculate the X25519 public key from a given X25519 secret key.
ParagonIE_Sodium_Compat::crypto_box_seal	public static	function	Anonymous public-key encryption. Only the recipient may decrypt messages.
ParagonIE_Sodium_Compat::CRYPTO_BOX_SEALBYTES		constant
ParagonIE_Sodium_Compat::crypto_box_seal_open	public static	function	Opens a message encrypted with crypto_box_seal(). Requires the recipient's keypair (sk || pk) to decrypt successfully.
ParagonIE_Sodium_Compat::crypto_box_secretkey	public static	function	Extract the secret key from a crypto_box keypair.
ParagonIE_Sodium_Compat::CRYPTO_BOX_SECRETKEYBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_BOX_SEEDBYTES		constant
ParagonIE_Sodium_Compat::crypto_box_seed_keypair	public static	function	Generate an X25519 keypair from a seed.
ParagonIE_Sodium_Compat::crypto_generichash	public static	function	Calculates a BLAKE2b hash, with an optional key.
ParagonIE_Sodium_Compat::CRYPTO_GENERICHASH_BYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_GENERICHASH_BYTES_MAX		constant
ParagonIE_Sodium_Compat::CRYPTO_GENERICHASH_BYTES_MIN		constant
ParagonIE_Sodium_Compat::crypto_generichash_final	public static	function	Get the final BLAKE2b hash output for a given context.
ParagonIE_Sodium_Compat::crypto_generichash_init	public static	function	Initialize a BLAKE2b hashing context, for use in a streaming interface.
ParagonIE_Sodium_Compat::crypto_generichash_init_salt_personal	public static	function	Initialize a BLAKE2b hashing context, for use in a streaming interface.
ParagonIE_Sodium_Compat::CRYPTO_GENERICHASH_KEYBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_GENERICHASH_KEYBYTES_MAX		constant
ParagonIE_Sodium_Compat::CRYPTO_GENERICHASH_KEYBYTES_MIN		constant
ParagonIE_Sodium_Compat::crypto_generichash_keygen	public static	function
ParagonIE_Sodium_Compat::crypto_generichash_update	public static	function	Update a BLAKE2b hashing context with additional data.
ParagonIE_Sodium_Compat::CRYPTO_KDF_BYTES_MAX		constant
ParagonIE_Sodium_Compat::CRYPTO_KDF_BYTES_MIN		constant
ParagonIE_Sodium_Compat::CRYPTO_KDF_CONTEXTBYTES		constant
ParagonIE_Sodium_Compat::crypto_kdf_derive_from_key	public static	function
ParagonIE_Sodium_Compat::CRYPTO_KDF_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_kdf_keygen	public static	function
ParagonIE_Sodium_Compat::crypto_kx	public static	function	Perform a key exchange, between a designated client and a server.
ParagonIE_Sodium_Compat::CRYPTO_KX_BYTES		constant
ParagonIE_Sodium_Compat::crypto_kx_client_session_keys	public static	function
ParagonIE_Sodium_Compat::crypto_kx_keypair	public static	function
ParagonIE_Sodium_Compat::CRYPTO_KX_KEYPAIRBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_KX_PRIMITIVE		constant
ParagonIE_Sodium_Compat::crypto_kx_publickey	public static	function
ParagonIE_Sodium_Compat::CRYPTO_KX_PUBLICKEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_kx_secretkey	public static	function
ParagonIE_Sodium_Compat::CRYPTO_KX_SECRETKEYBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_KX_SEEDBYTES		constant
ParagonIE_Sodium_Compat::crypto_kx_seed_keypair	public static	function
ParagonIE_Sodium_Compat::crypto_kx_server_session_keys	public static	function
ParagonIE_Sodium_Compat::CRYPTO_KX_SESSIONKEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_pwhash	public static	function	@psalm-suppress MixedArgument
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_ALG_ARGON2I13		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_ALG_ARGON2ID13		constant
ParagonIE_Sodium_Compat::crypto_pwhash_is_available	public static	function	!Exclusive to sodium_compat!
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_MEMLIMIT_MODERATE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_MEMLIMIT_SENSITIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_OPSLIMIT_MODERATE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_OPSLIMIT_SENSITIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_SALTBYTES		constant
ParagonIE_Sodium_Compat::crypto_pwhash_scryptsalsa208sha256	public static	function
ParagonIE_Sodium_Compat::crypto_pwhash_scryptsalsa208sha256_is_available	public static	function	!Exclusive to sodium_compat!
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_INTERACTIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_SENSITIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_INTERACTIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_SENSITIVE		constant
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_SCRYPTSALSA208SHA256_SALTBYTES		constant
ParagonIE_Sodium_Compat::crypto_pwhash_scryptsalsa208sha256_str	public static	function
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_SCRYPTSALSA208SHA256_STRPREFIX		constant
ParagonIE_Sodium_Compat::crypto_pwhash_scryptsalsa208sha256_str_verify	public static	function
ParagonIE_Sodium_Compat::crypto_pwhash_str	public static	function	@psalm-suppress MixedArgument
ParagonIE_Sodium_Compat::CRYPTO_PWHASH_STRPREFIX		constant
ParagonIE_Sodium_Compat::crypto_pwhash_str_needs_rehash	public static	function	Do we need to rehash this password?
ParagonIE_Sodium_Compat::crypto_pwhash_str_verify	public static	function	@psalm-suppress MixedArgument
ParagonIE_Sodium_Compat::crypto_scalarmult	public static	function	Calculate the shared secret between your secret key and your recipient's public key.
ParagonIE_Sodium_Compat::crypto_scalarmult_base	public static	function	Calculate an X25519 public key from an X25519 secret key.
ParagonIE_Sodium_Compat::CRYPTO_SCALARMULT_BYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_SCALARMULT_SCALARBYTES		constant
ParagonIE_Sodium_Compat::crypto_secretbox	public static	function	Authenticated symmetric-key encryption.
ParagonIE_Sodium_Compat::CRYPTO_SECRETBOX_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_secretbox_keygen	public static	function	Return a secure random key for use with crypto_secretbox
ParagonIE_Sodium_Compat::CRYPTO_SECRETBOX_MACBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_SECRETBOX_NONCEBYTES		constant
ParagonIE_Sodium_Compat::crypto_secretbox_open	public static	function	Decrypts a message previously encrypted with crypto_secretbox().
ParagonIE_Sodium_Compat::crypto_secretbox_xchacha20poly1305	public static	function	Authenticated symmetric-key encryption.
ParagonIE_Sodium_Compat::crypto_secretbox_xchacha20poly1305_open	public static	function	Decrypts a message previously encrypted with crypto_secretbox_xchacha20poly1305().
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_ABYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES		constant
ParagonIE_Sodium_Compat::crypto_secretstream_xchacha20poly1305_init_pull	public static	function
ParagonIE_Sodium_Compat::crypto_secretstream_xchacha20poly1305_init_push	public static	function
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_secretstream_xchacha20poly1305_keygen	public static	function
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_MESSAGEBYTES_MAX		constant
ParagonIE_Sodium_Compat::crypto_secretstream_xchacha20poly1305_pull	public static	function
ParagonIE_Sodium_Compat::crypto_secretstream_xchacha20poly1305_push	public static	function
ParagonIE_Sodium_Compat::crypto_secretstream_xchacha20poly1305_rekey	public static	function
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_FINAL		constant
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_PULL		constant
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_PUSH		constant
ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_REKEY		constant
ParagonIE_Sodium_Compat::crypto_shorthash	public static	function	Calculates a SipHash-2-4 hash of a message for a given key.
ParagonIE_Sodium_Compat::CRYPTO_SHORTHASH_BYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_SHORTHASH_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_shorthash_keygen	public static	function	Return a secure random key for use with crypto_shorthash
ParagonIE_Sodium_Compat::crypto_sign	public static	function	Returns a signed message. You probably want crypto_sign_detached() instead, which only returns the signature.
ParagonIE_Sodium_Compat::CRYPTO_SIGN_BYTES		constant
ParagonIE_Sodium_Compat::crypto_sign_detached	public static	function	Calculate the Ed25519 signature of a message and return ONLY the signature.
ParagonIE_Sodium_Compat::crypto_sign_ed25519_pk_to_curve25519	public static	function	Convert an Ed25519 public key to a Curve25519 public key
ParagonIE_Sodium_Compat::crypto_sign_ed25519_sk_to_curve25519	public static	function	Convert an Ed25519 secret key to a Curve25519 secret key
ParagonIE_Sodium_Compat::crypto_sign_keypair	public static	function	Generate a new random Ed25519 keypair.
ParagonIE_Sodium_Compat::CRYPTO_SIGN_KEYPAIRBYTES		constant
ParagonIE_Sodium_Compat::crypto_sign_keypair_from_secretkey_and_publickey	public static	function
ParagonIE_Sodium_Compat::crypto_sign_open	public static	function	Validates a signed message then returns the message.
ParagonIE_Sodium_Compat::crypto_sign_publickey	public static	function	Extract an Ed25519 public key from an Ed25519 keypair.
ParagonIE_Sodium_Compat::CRYPTO_SIGN_PUBLICKEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_sign_publickey_from_secretkey	public static	function	Calculate an Ed25519 public key from an Ed25519 secret key.
ParagonIE_Sodium_Compat::crypto_sign_secretkey	public static	function	Extract an Ed25519 secret key from an Ed25519 keypair.
ParagonIE_Sodium_Compat::CRYPTO_SIGN_SECRETKEYBYTES		constant
ParagonIE_Sodium_Compat::CRYPTO_SIGN_SEEDBYTES		constant
ParagonIE_Sodium_Compat::crypto_sign_seed_keypair	public static	function	Generate an Ed25519 keypair from a seed.
ParagonIE_Sodium_Compat::crypto_sign_verify_detached	public static	function	Verify the Ed25519 signature of a message.
ParagonIE_Sodium_Compat::crypto_stream	public static	function	Expand a key and nonce into a keystream of pseudorandom bytes.
ParagonIE_Sodium_Compat::CRYPTO_STREAM_KEYBYTES		constant
ParagonIE_Sodium_Compat::crypto_stream_keygen	public static	function	Return a secure random key for use with crypto_stream
ParagonIE_Sodium_Compat::CRYPTO_STREAM_NONCEBYTES		constant
ParagonIE_Sodium_Compat::crypto_stream_xor	public static	function	DANGER! UNAUTHENTICATED ENCRYPTION!
ParagonIE_Sodium_Compat::hex2bin	public static	function	Cache-timing-safe implementation of hex2bin().
ParagonIE_Sodium_Compat::increment	public static	function	Increase a string (little endian)
ParagonIE_Sodium_Compat::LIBRARY_MAJOR_VERSION		constant
ParagonIE_Sodium_Compat::LIBRARY_MINOR_VERSION		constant
ParagonIE_Sodium_Compat::library_version_major	public static	function	The equivalent to the libsodium minor version we aim to be compatible with (sans pwhash and memzero).
ParagonIE_Sodium_Compat::LIBRARY_VERSION_MAJOR		constant
ParagonIE_Sodium_Compat::library_version_minor	public static	function	The equivalent to the libsodium minor version we aim to be compatible with (sans pwhash and memzero).
ParagonIE_Sodium_Compat::LIBRARY_VERSION_MINOR		constant
ParagonIE_Sodium_Compat::memcmp	public static	function	Compare two strings.
ParagonIE_Sodium_Compat::memzero	public static	function	It's actually not possible to zero memory buffers in PHP. You need the native library for that.
ParagonIE_Sodium_Compat::pad	public static	function
ParagonIE_Sodium_Compat::polyfill_is_fast	public static	function	Will sodium_compat run fast on the current hardware and PHP configuration?
ParagonIE_Sodium_Compat::randombytes_buf	public static	function	Generate a string of bytes from the kernel's CSPRNG. Proudly uses /dev/urandom (if getrandom(2) is not available).
ParagonIE_Sodium_Compat::randombytes_random16	public static	function	Generate a random 16-bit integer.
ParagonIE_Sodium_Compat::randombytes_uniform	public static	function	Generate an integer between 0 and $range (non-inclusive).
ParagonIE_Sodium_Compat::runtime_speed_test	public static	function	Runtime testing method for 32-bit platforms.
ParagonIE_Sodium_Compat::unpad	public static	function
ParagonIE_Sodium_Compat::useNewSodiumAPI	protected static	function	Libsodium as implemented in PHP 7.2 and/or ext/sodium (via PECL)
ParagonIE_Sodium_Compat::use_fallback	protected static	function	Should we use the libsodium core function instead? This is always a good idea, if it's available. (Unless we're in the middle of running our unit test suite.)
ParagonIE_Sodium_Compat::version_string	public static	function	This emulates libsodium's version_string() function, except ours is prefixed with 'polyfill-'.
ParagonIE_Sodium_Compat::VERSION_STRING		constant