mcrypt_module_is_block_mode
In the text example:
$key = substr(md5('very secret key'), 0, $ks);
Builds a key of $ks/2 effective bytes.
mcrypt_module_open
(PHP 4 >= 4.0.2, PHP 5)
mcrypt_module_open — Opens the module of the algorithm and the mode to be used
Beschreibung
resource mcrypt_module_open
( string
$algorithm
, string $algorithm_directory
, string $mode
, string $mode_directory
)
This function opens the module of the algorithm and the mode to be used.
The name of the algorithm is specified in algorithm, e.g. "twofish" or is
one of the MCRYPT_ciphername constants. The module is closed by calling
mcrypt_module_close().
Parameter-Liste
-
algorithm -
The algorithm to be used.
-
algorithm_directory -
The
algorithm_directoryparameter is used to locate the encryption module. When you supply a directory name, it is used. When you set it to an empty string (""), the value set by the mcrypt.algorithms_dir php.ini directive is used. When it is not set, the default directory that is used is the one that was compiled into libmcrypt (usually /usr/local/lib/libmcrypt). -
mode -
The mode to be used.
-
mode_directory -
The
mode_directoryparameter is used to locate the encryption module. When you supply a directory name, it is used. When you set it to an empty string (""), the value set by the mcrypt.modes_dir php.ini directive is used. When it is not set, the default directory that is used is the one that was compiled-in into libmcrypt (usually /usr/local/lib/libmcrypt).
Rückgabewerte
Normally it returns an encryption descriptor, or FALSE on error.
Beispiele
Beispiel #1 mcrypt_module_open() Examples
<?php
$td = mcrypt_module_open(MCRYPT_DES, '',
MCRYPT_MODE_ECB, '/usr/lib/mcrypt-modes');
$td = mcrypt_module_open('rijndael-256', '', 'ofb', '');
?>
The first line in the example above will try to open the DES cipher from the default directory and the EBC mode from the directory /usr/lib/mcrypt-modes. The second example uses strings as name for the cipher and mode, this only works when the extension is linked against libmcrypt 2.4.x or 2.5.x.
Beispiel #2 Using mcrypt_module_open() in encryption
<?php
/* Open the cipher */
$td = mcrypt_module_open('rijndael-256', '', 'ofb', '');
/* Create the IV and determine the keysize length, use MCRYPT_RAND
* on Windows instead */
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_RANDOM);
$ks = mcrypt_enc_get_key_size($td);
/* Create key */
$key = substr(md5('very secret key'), 0, $ks);
/* Intialize encryption */
mcrypt_generic_init($td, $key, $iv);
/* Encrypt data */
$encrypted = mcrypt_generic($td, 'This is very important data');
/* Terminate encryption handler */
mcrypt_generic_deinit($td);
/* Initialize encryption module for decryption */
mcrypt_generic_init($td, $key, $iv);
/* Decrypt encrypted string */
$decrypted = mdecrypt_generic($td, $encrypted);
/* Terminate decryption handle and close module */
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
/* Show string */
echo trim($decrypted) . "\n";
?>
Siehe auch
- mcrypt_module_close() - Closes the mcrypt module
- mcrypt_generic() - This function encrypts data
- mdecrypt_generic() - Decrypts data
- mcrypt_generic_init() - This function initializes all buffers needed for encryption
- mcrypt_generic_deinit() - This function deinitializes an encryption module
add a note
User Contributed Notesmcrypt_module_open
Mon
03-Mar-2006 12:27
03-Mar-2006 12:27
01-Aug-2003 05:14
Doing a trim($decrypted) will remove the null padding that may occur as a result of decryption.
The problem is if you're encrypting something like a MSWord document which can commonly end with nulls. The result $decrypted will be smaller than the original cleartext - which will then fail to open in MSOffice.
To get around this, make sure you store the length of the original cleartext, and when you decrypt it, do:
$decrypted = substr(mdecrypt_generic($td, $encrypted), 0, $originalLength);