(PHP 4, PHP 5)
mcrypt_get_key_size — Gets the key size of the specified cipher
$cipher
)$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().
cipher
MCRYPT_ciphername 常量中的一个，或者是字符串值的算法名称。
mode
MCRYPT_MODE_modename 常量中的一个，或以下字符串中的一个："ecb"，"cbc"，"cfb"，"ofb"，"nofb" 和 "stream"。
Returns the maximum supported key size of the algorithm in bytes
或者在失败时返回 FALSE.
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.
以上例程会输出：
24
Robin (2010-03-09 04:43:36)
While not specified in the description, this function, just like mcrypt_enc_get_key_size(), returns the cipher's largest key size in BYTES.