mcrypt

加密算法

## mcrypt_list_algorithms
Array
(
    [0] => cast-128
    [1] => gost
    [2] => rijndael-128
    [3] => twofish
    [4] => arcfour
    [5] => cast-256
    [6] => loki97
    [7] => rijndael-192
    [8] => saferplus
    [9] => wake
    [10] => blowfish-compat
    [11] => des
    [12] => rijndael-256
    [13] => serpent
    [14] => xtea
    [15] => blowfish
    [16] => enigma
    [17] => rc2
    [18] => tripledes
)

分组大小

mcrypt_enc_get_iv_size()

iv

• 向量大小，通常等于分组大小
• ecb模式下初始向量会被忽略
• CFB、CBC、STREAM、nOFB、OFB模式必须提供初始向量，初始向量要求是随机的