#用aes加密，再用base64  encode

def aes_encrypt(data): 

    from Crypto.Cipher import AES

    import base64

    key=settings.aes_key  #加密时使用的key，只能是长度16,24和32的字符串

    BS = AES.block_size

    pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)

    cipher = AES.new(key)

    encrypted = cipher.encrypt(pad(data))  #aes加密

    result = base64.b64encode(encrypted)  #base64 encode

    return result  

#把加密的数据，用base64  decode，再用aes解密

def aes_decode(data):

    key=settings.aes_key

    from Crypto.Cipher import AES

    import os

    import base64

    unpad = lambda s : s[0:-ord(s[-1])]

    cipher = AES.new(key)

    result2 = base64.b64decode(data)

    decrypted = unpad(cipher.decrypt(result2))

    return  decrypted