mcrypt_module_get_supported_key_sizes Returns an array with the supported keysizes of the opened algorithm arraymcrypt_module_get_supported_key_sizes stringalgorithm stringlib_dir Returns an array with the key sizes supported by the specified algorithm. If it returns an empty array then all key sizes between 1 and mcrypt_module_get_algo_key_size are supported by the algorithm. The optional lib_dir parameter can contain the location where the mode module is on the system. See also mcrypt_enc_get_supported_key_sizes which is used on open encryption modules.