<?php
namespace ParagonIE\CipherSweet\Backend\Key;
use ParagonIE\CipherSweet\Contract\BackendInterface;
use ParagonIE\ConstantTime\Binary;
/**
* Class SymmetricKey
* @package ParagonIE\CipherSweet\Backend\Key
*/
class SymmetricKey
{
/**
* @var BackendInterface $Backend
*/
private $backend;
/**
* @var string $keyMaterial
*/
private $keyMaterial;
/**
* SymmetricKey constructor.
*
* @param BackendInterface $backend
* @param string $rawKeyMaterial
*/
public function __construct(BackendInterface $backend, $rawKeyMaterial)
{
/** @psalm-suppress RedundantConditionGivenDocblockType */
if (!\is_string($rawKeyMaterial)) {
throw new \TypeError('String expected');
}
$this->backend = $backend;
$this->keyMaterial = $rawKeyMaterial;
}
/**
* Attempt to wipe memory.
*/
public function __destruct()
{
if (\extension_loaded('sodium')) {
\sodium_memzero($this->keyMaterial);
} elseif (\extension_loaded('libsodium')) {
\Sodium\memzero($this->keyMaterial);
} else {
// Worst-case scenario: Best-ditch effort to wipe memory
$m = \str_repeat("\xff", (int) Binary::safeStrlen($this->keyMaterial));
$this->keyMaterial ^= ($this->keyMaterial ^ $m);
unset($this->keyMaterial);
}
}
/**
* @return string
*/
public function getRawKey()
{
return $this->keyMaterial;
}
}
|
Download
