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mcrypt_get_key_size

(PHP 4, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0)

mcrypt_get_key_sizeGets the key size of the specified cipher

Warning

This function has been DEPRECATED as of PHP 7.1.0 and REMOVED as of PHP 7.2.0. Relying on this function is highly discouraged.

Description

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

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

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User Contributed Notes 1 note

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Robin
10 years ago
While not specified in the description, this function, just like mcrypt_enc_get_key_size(), returns the cipher's largest key size in BYTES.
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