mcrypt_get_key_size

Gets the key size of the specified cipher

Warning

This function has been DEPRECATED as of PHP 7.1.0. Relying on this function is highly discouraged.

Description

int mcrypt_get_key_size ( int $cipher )
int mcrypt_get_key_size ( string $cipher , string $mode )

The first prototype is when linked against libmcrypt 2.2.x, the second when linked against libmcrypt 2.4.x or 2.5.x.

mcrypt_get_key_size is used to get the size of a key of the specified cipher (in combination with an encryption mode).

It is more useful to use the mcrypt_enc_get_key_size function as this uses the resource returned by mcrypt_module_open.

Parameters

cipher

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

mode

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

Return Values

Returns the maximum supported key size of the algorithm in bytes or FALSE on failure.

Examples

Example #1 mcrypt_get_key_size Example

<?php
    
echo mcrypt_get_key_size('tripledes''ecb');
?>

The example above shows how to use this function when linked against libmcrypt 2.4.x or 2.5.x.

The above example will output:

24

See Also

  • mcrypt_get_block_size
  • mcrypt_enc_get_key_size
  • mcrypt_encrypt