Using mcrypt_get_key_size() to Retrieve the Key Size of a Specified Cipher in PHP
The article explains the PHP mcrypt_get_key_size() function, its prototypes for different libmcrypt versions, the meaning of its cipher and mode parameters, the return value indicating maximum key size, and provides a practical code example demonstrating its usage.
The mcrypt_get_key_size() function in PHP returns the key size required by a given encryption algorithm and mode.
Prototype (for libmcrypt 2.2.x): int mcrypt_get_key_size(string $cipher, string $mode) Prototype (for libmcrypt 2.4.x or 2.5.x): same signature, but behavior may differ based on library version.
This function is used to obtain the key length that the specified $cipher algorithm and $mode require.
Parameters
cipher : One of the MCRYPT_ciphername constants or a string naming the algorithm.
mode : One of the MCRYPT_MODE_modename constants or one of the strings "ecb", "cbc", "cfb", "ofb", "nofb", "stream".
Return value : The maximum supported key size in bytes for the algorithm, or FALSE on failure.
Example :
<?php<br/>echo mcrypt_get_key_size('tripledes', 'ecb');<br/>?>Signed-in readers can open the original source through BestHub's protected redirect.
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