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

说明

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().

参数

algorithm: The algorithm to be used.
algorithm_directory: The algorithm_directory parameter 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_directory parameter 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).

返回值

Normally it returns an encryption descriptor, or FALSE on error.

范例

Example #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.

Example #2 Using mcrypt_module_open() in encryption


<?php
    
    $td = mcrypt_module_open('rijndael-256', '', 'ofb', '');

    
    $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_RANDOM);
    $ks = mcrypt_enc_get_key_size($td);

    
    $key = substr(md5('very secret key'), 0, $ks);

    
    mcrypt_generic_init($td, $key, $iv);

    
    $encrypted = mcrypt_generic($td, 'This is very important data');

    
    mcrypt_generic_deinit($td);

    
    mcrypt_generic_init($td, $key, $iv);

    
    $decrypted = mdecrypt_generic($td, $encrypted);

    
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);

    
    echo trim($decrypted) . "
";
?>

参见

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