public static function ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10_base in Automatic Updates 7

Same name and namespace in other branches

1. 8 vendor/paragonie/sodium_compat/src/Core/X25519.php \ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10_base()

@internal You should not use this directly from another application

Parameters

string $n:

Return value

string

Throws

SodiumException

TypeError

1 call to ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10_base()

ParagonIE_Sodium_Crypto::scalarmult_base in vendor/paragonie/sodium_compat/src/Crypto.php

ECDH over Curve25519, using the basepoint. Used to get a secret key from a public key.

File

vendor/paragonie/sodium_compat/src/Core/X25519.php, line 300

Class

ParagonIE_Sodium_Core_X25519

Class ParagonIE_Sodium_Core_X25519

Code

public static function crypto_scalarmult_curve25519_ref10_base($n) {

  # for (i = 0;i < 32;++i) e[i] = n[i];
  $e = '' . $n;

  # e[0] &= 248;
  $e[0] = self::intToChr(self::chrToInt($e[0]) & 248);

  # e[31] &= 127;

  # e[31] |= 64;
  $e[31] = self::intToChr(self::chrToInt($e[31]) & 127 | 64);
  $A = self::ge_scalarmult_base($e);
  if (!$A->Y instanceof ParagonIE_Sodium_Core_Curve25519_Fe || !$A->Z instanceof ParagonIE_Sodium_Core_Curve25519_Fe) {
    throw new TypeError('Null points encountered');
  }
  $pk = self::edwards_to_montgomery($A->Y, $A->Z);
  return self::fe_tobytes($pk);
}