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added more comments to crypter class.

This commit is contained in:
Taylor Otwell 2011-09-20 23:48:35 -05:00
parent 600e411ad4
commit b9b9711921
1 changed files with 39 additions and 22 deletions
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61
laravel/security/crypter.php
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@ -26,6 +26,9 @@ class Crypter {
/**
* Create a new Crypter instance.
*
* A valid cipher and mode supported by the Mcrypt extension must be given to the constructor.
* Also, an encryption key (typically from the application configuration) must be specified.
*
* @param string $cipher
* @param string $mode
* @param string $key
@ -33,9 +36,9 @@ class Crypter {
*/
public function __construct($cipher, $mode, $key)
{
$this->cipher = $cipher;
$this->mode = $mode;
$this->key = $key;
$this->mode = $mode;
$this->cipher = $cipher;
if (trim((string) $this->key) === '')
{
@ -46,48 +49,62 @@ public function __construct($cipher, $mode, $key)
/**
* Encrypt a string using Mcrypt.
*
* The string will be encrypted using the cipher and mode specified when the crypter
* instance was created, and the final result will be base64 encoded.
*
* <code>
* // Encrypt a string using the Mcrypt PHP extension
* $encrypted = Crypter::encrpt('secret');
* </code>
*
* @param string $value
* @return string
*/
public function encrypt($value)
{
$iv = mcrypt_create_iv($this->iv_size(), $this->randomizer());
// Determine the most appropriate random number generator for the operating
// system and environment the application is running on.
if (defined('MCRYPT_DEV_URANDOM'))
{
$randomizer = MCRYPT_DEV_URANDOM;
}
elseif (defined('MCRYPT_DEV_RANDOM'))
{
$randomizer = MCRYPT_DEV_RANDOM;
}
else
{
$randomizer = MCRYPT_RAND;
}
$iv = mcrypt_create_iv($this->iv_size(), $randomizer);
return base64_encode($iv.mcrypt_encrypt($this->cipher, $this->key, $value, $this->mode, $iv));
}
/**
* Get the random number source available to the OS.
*
* @return int
*/
protected function randomizer()
{
if (defined('MCRYPT_DEV_URANDOM'))
{
return MCRYPT_DEV_URANDOM;
}
elseif (defined('MCRYPT_DEV_RANDOM'))
{
return MCRYPT_DEV_RANDOM;
}
return MCRYPT_RAND;
}
/**
* Decrypt a string using Mcrypt.
*
* The string will be decrypted using the cipher and mode specified when the crypter was created.
*
* <code>
* // Decrypt a string using the Mcrypt PHP extension
* $decrypted = Crypter::decrypt($secret);
* </code>
*
* @param string $value
* @return string
*/
public function decrypt($value)
{
// Since all encrypted strings generated by this class are base64 encoded, we will
// first attempt to base64 decode the string. If we can't do it, we'll bail out.
if ( ! is_string($value = base64_decode($value, true)))
{
throw new \Exception('Decryption error. Input value is not valid base64 data.');
}
// Extract the input vector and the encrypted string from the value
list($iv, $value) = array(substr($value, 0, $this->iv_size()), substr($value, $this->iv_size()));
return rtrim(mcrypt_decrypt($this->cipher, $this->key, $value, $this->mode, $iv), "\0");