Mcrypt
- Introduction
- Installing/Configuring
- Predefined Constants
- Mcrypt ciphers
- Examples
- Mcrypt Functions
- mcrypt_cbc — Encrypts/decrypts data in CBC mode
- mcrypt_cfb — Encrypts/decrypts data in CFB mode
- mcrypt_create_iv — Creates an initialization vector (IV) from a random source
- mcrypt_decrypt — Decrypts crypttext with given parameters
- mcrypt_ecb — Deprecated: Encrypts/decrypts data in ECB mode
- mcrypt_enc_get_algorithms_name — Returns the name of the opened algorithm
- mcrypt_enc_get_block_size — Returns the blocksize of the opened algorithm
- mcrypt_enc_get_iv_size — Returns the size of the IV of the opened algorithm
- mcrypt_enc_get_key_size — Returns the maximum supported keysize of the opened mode
- mcrypt_enc_get_modes_name — Returns the name of the opened mode
- mcrypt_enc_get_supported_key_sizes — Returns an array with the supported keysizes of the opened algorithm
- mcrypt_enc_is_block_algorithm_mode — Checks whether the encryption of the opened mode works on blocks
- mcrypt_enc_is_block_algorithm — Checks whether the algorithm of the opened mode is a block algorithm
- mcrypt_enc_is_block_mode — Checks whether the opened mode outputs blocks
- mcrypt_enc_self_test — Runs a self test on the opened module
- mcrypt_encrypt — Encrypts plaintext with given parameters
- mcrypt_generic_deinit — This function deinitializes an encryption module
- mcrypt_generic_end — This function terminates encryption
- mcrypt_generic_init — This function initializes all buffers needed for encryption
- mcrypt_generic — This function encrypts data
- mcrypt_get_block_size — Gets the block size of the specified cipher
- mcrypt_get_cipher_name — Gets the name of the specified cipher
- mcrypt_get_iv_size — Returns the size of the IV belonging to a specific cipher/mode combination
- mcrypt_get_key_size — Gets the key size of the specified cipher
- mcrypt_list_algorithms — Gets an array of all supported ciphers
- mcrypt_list_modes — Gets an array of all supported modes
- mcrypt_module_close — Closes the mcrypt module
- mcrypt_module_get_algo_block_size — Returns the blocksize of the specified algorithm
- mcrypt_module_get_algo_key_size — Returns the maximum supported keysize of the opened mode
- mcrypt_module_get_supported_key_sizes — Returns an array with the supported keysizes of the opened algorithm
- mcrypt_module_is_block_algorithm_mode — Returns if the specified module is a block algorithm or not
- mcrypt_module_is_block_algorithm — This function checks whether the specified algorithm is a block algorithm
- mcrypt_module_is_block_mode — Returns if the specified mode outputs blocks or not
- mcrypt_module_open — Opens the module of the algorithm and the mode to be used
- mcrypt_module_self_test — This function runs a self test on the specified module
- mcrypt_ofb — Encrypts/decrypts data in OFB mode
- mdecrypt_generic — Decrypts data
Коментарии
people using phpmyadmin are redirected to this manual if they don't have mcrypt installed. If you want to install mcrypt on debian, first check your php version:
yourserver# php --version
Then install the appropriate version of mcrypt (php5-mcrypt if your php version is 5.x)
yourserver# apt-get install php4-mcrypt
...or...
yourserver# apt-get install php5-mcrypt
If you want a quick way to see what ciphers, modes, key, block and iv sizes are supported on your server, try something like the following.
Note: I used this simple bash: `locate libmcrypt` from terminal on Mac OS X to determine the install paths to the algorithms and modes directories. Lots of function calls generate warnings for certain ciphers, hence the use of error suppression.
<?php
$modes = mcrypt_list_modes();
$algorithms = mcrypt_list_algorithms();
foreach($algorithms as $cipher)
{
echo "<h1 style=\"border-top:1px solid black;\">".$cipher."</h1>\n";
foreach($modes as $mode)
{
echo "<h3>".$mode."</h3>\n";
@$td = mcrypt_module_open(
$cipher,
'/usr/local/libmcrypt-2.5.8/modules/algorithms/',
$mode,
'/usr/local/libmcrypt-2.5.8/modules/modes/');
@$key_size = mcrypt_enc_get_key_size($td);
@$block_size = mcrypt_get_block_size($cipher,$mode);
@$iv_size = mcrypt_get_iv_size($cipher, $mode);
@mcrypt_module_close($td);
echo "
<pre>
key_size: ". ($key_size?$key_size:'n/a')
." block_size: ". ($block_size?$block_size:'n/a')
." iv_size: ". ($iv_size?$iv_size:'n/a')
." </pre>\n";
$td=NULL;
$key_size=NULL;
$block_size=NULL;
$iv_size=NULL;
}
}
?>
These are two simple functions I built for 256-bit encryption/decryption with mcrypt. I've decided to use MCRYPT_RIJNDAEL_128 because it's AES-compliant, and MCRYPT_MODE_CBC. (ECB mode is inadequate for many purposes because it does not use an IV.)
This function stores a hash of the data to verify that the data was decrypted successfully, but this could be easily removed if necessary.
<?php
function encrypt($decrypted, $password, $salt='!kQm*fF3pXe1Kbm%9') {
// Build a 256-bit $key which is a SHA256 hash of $salt and $password.
$key = hash('SHA256', $salt . $password, true);
// Build $iv and $iv_base64. We use a block size of 128 bits (AES compliant) and CBC mode. (Note: ECB mode is inadequate as IV is not used.)
srand(); $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC), MCRYPT_RAND);
if (strlen($iv_base64 = rtrim(base64_encode($iv), '=')) != 22) return false;
// Encrypt $decrypted and an MD5 of $decrypted using $key. MD5 is fine to use here because it's just to verify successful decryption.
$encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $decrypted . md5($decrypted), MCRYPT_MODE_CBC, $iv));
// We're done!
return $iv_base64 . $encrypted;
}
function decrypt($encrypted, $password, $salt='!kQm*fF3pXe1Kbm%9') {
// Build a 256-bit $key which is a SHA256 hash of $salt and $password.
$key = hash('SHA256', $salt . $password, true);
// Retrieve $iv which is the first 22 characters plus ==, base64_decoded.
$iv = base64_decode(substr($encrypted, 0, 22) . '==');
// Remove $iv from $encrypted.
$encrypted = substr($encrypted, 22);
// Decrypt the data. rtrim won't corrupt the data because the last 32 characters are the md5 hash; thus any \0 character has to be padding.
$decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($encrypted), MCRYPT_MODE_CBC, $iv), "\0\4");
// Retrieve $hash which is the last 32 characters of $decrypted.
$hash = substr($decrypted, -32);
// Remove the last 32 characters from $decrypted.
$decrypted = substr($decrypted, 0, -32);
// Integrity check. If this fails, either the data is corrupted, or the password/salt was incorrect.
if (md5($decrypted) != $hash) return false;
// Yay!
return $decrypted;
}
?>
Note that there are severe performance problems with PHP mcrypt on many CentOS versions. Please see this CentOS bug:http://bugs.centos.org/view.php?id=8954
This was posted before by another user but has been downvoted. I just wanted to confirm that we suffered massive performance issues related to mcrypt on CentOS (PHP 5.6.32) that are not present in other flavors of Linux.
A sampling of 25,000 encrypts/decrypts takes 4-5x longer when running mcrypt on Centos 7 as compared to Ubuntu. Switching out mcrypt for OpenSSL on Centos will result in a massive increase in performance.
For lower traffic website it can be negligible, but when you start seeing significant traffic/load it will quickly bring down a server.
Issue Solved when installing php7.2-mcrypt
I was also facing the same issue. Check this link https://stackoverflow.com/q/48275494/7713811 to get the right solution for installing it in PHP
If you're wanting to use mcrypt on a newer version of PHP where it's been deprecated try the shim for it instead:
https://github.com/phpseclib/mcrypt_compat