function mcrypt-encrypt - Encrypts plaintext with given parameters

Description

string mcrypt_encrypt ( string $cipher , string $key , string $data , string $mode [, string $iv ] )

Encrypts the data and returns it.

Parameters

cipher

One of the MCRYPT_ciphername constants, or the name of the algorithm as string.

key

The key with which the data will be encrypted. If it's smaller than the required keysize, it is padded with '\0'. It is better not to use ASCII strings for keys.

It is recommended to use the mhash functions to create a key from a string.

data

The data that will be encrypted with the given cipher and mode. If the size of the data is not n * blocksize, the data will be padded with '\0'.

The returned crypttext can be larger than the size of the data that was given by data.

mode

One of the MCRYPT_MODE_modename constants, or one of the following strings: "ecb", "cbc", "cfb", "ofb", "nofb" or "stream".

iv

Used for the initialization in CBC, CFB, OFB modes, and in some algorithms in STREAM mode. If you do not supply an IV, while it is needed for an algorithm, the function issues a warning and uses an IV with all its bytes set to '\0'.

Return Values

Returns the encrypted data, as a string.

Examples

Example #1 mcrypt_encrypt() Example

 <?php
    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    $key = "This is a very secret key";
    $text = "Meet me at 11 o'clock behind the monument.";
    echo strlen($text) . "\n";

    $crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $text, MCRYPT_MODE_ECB, $iv);
    echo strlen($crypttext) . "\n";
?>

The above example will output:

 42 64

See also mcrypt_module_open() for a more advanced API and an example.