mcrypt
PHP Manual

mcrypt_module_get_algo_key_size

(PHP 4 >= 4.0.2, PHP 5)

mcrypt_module_get_algo_key_size — Returns the maximum supported keysize of the opened mode

Description

int mcrypt_module_get_algo_key_size ( string $algorithm [, string $lib_dir ] )

This function returns the maximum supported key size of the algorithm specified in bytes. The optional lib_dir parameter can contain the location where the mode module is on the system.


mcrypt
PHP Manual