python的des和3des加解密

pyDes.des(key, [mode], [IV], [pad], [padmode])
pyDes.triple_des(key, [mode], [IV], [pad], [padmode])

key     -> Bytes containing the encryption key. 8 bytes for DES, 16 or 24 bytes
       for Triple DES
mode    -> Optional argument for encryption type, can be either
       pyDes.ECB (Electronic Code Book) or pyDes.CBC (Cypher Block Chaining)
IV      -> Optional Initial Value bytes, must be supplied if using CBC mode.
       Length must be 8 bytes.
pad     -> Optional argument, set the pad character (PAD_NORMAL) to use during
       all encrypt/decrpt operations done with this instance.
padmode -> Optional argument, set the padding mode (PAD_NORMAL or PAD_PKCS5)
       to use during all encrypt/decrpt operations done with this instance.

Example
-------
from pyDes import *

data = "Please encrypt my data"
k = des("DESCRYPT", CBC, "