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