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<?php
class ParagonIE_Sodium_Core32_SecretStream_State {
protected $key;
protected $counter;
protected $nonce;
protected $_pad;
public function __construct($key, $nonce = null) {
$this->key = $key;
$this->counter = 1;
if (is_null($nonce)) {
$nonce = str_repeat("\0", 12);
}
$this->nonce = str_pad($nonce, 12, "\0", STR_PAD_RIGHT);
$this->_pad = str_repeat("\0", 4);
}
public function counterReset() {
$this->counter = 1;
$this->_pad = str_repeat("\0", 4);
return $this;
}
public function getKey() {
return $this->key;
}
public function getCounter() {
return ParagonIE_Sodium_Core32_Util::store32_le($this->counter);
}
public function getNonce() {
if (!is_string($this->nonce)) {
$this->nonce = str_repeat("\0", 12);
}
if (ParagonIE_Sodium_Core32_Util::strlen($this->nonce) !== 12) {
$this->nonce = str_pad($this->nonce, 12, "\0", STR_PAD_RIGHT);
}
return $this->nonce;
}
public function getCombinedNonce() {
return $this
->getCounter() . ParagonIE_Sodium_Core32_Util::substr($this
->getNonce(), 0, 8);
}
public function incrementCounter() {
++$this->counter;
return $this;
}
public function needsRekey() {
return ($this->counter & 0xffff) === 0;
}
public function rekey($newKeyAndNonce) {
$this->key = ParagonIE_Sodium_Core32_Util::substr($newKeyAndNonce, 0, 32);
$this->nonce = str_pad(ParagonIE_Sodium_Core32_Util::substr($newKeyAndNonce, 32), 12, "\0", STR_PAD_RIGHT);
return $this;
}
public function xorNonce($str) {
$this->nonce = ParagonIE_Sodium_Core32_Util::xorStrings($this
->getNonce(), str_pad(ParagonIE_Sodium_Core32_Util::substr($str, 0, 8), 12, "\0", STR_PAD_RIGHT));
return $this;
}
public static function fromString($string) {
$state = new ParagonIE_Sodium_Core32_SecretStream_State(ParagonIE_Sodium_Core32_Util::substr($string, 0, 32));
$state->counter = ParagonIE_Sodium_Core32_Util::load_4(ParagonIE_Sodium_Core32_Util::substr($string, 32, 4));
$state->nonce = ParagonIE_Sodium_Core32_Util::substr($string, 36, 12);
$state->_pad = ParagonIE_Sodium_Core32_Util::substr($string, 48, 8);
return $state;
}
public function toString() {
return $this->key . $this
->getCounter() . $this->nonce . $this->_pad;
}
}