Created
May 20, 2013 02:17
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Encryption using pycrypto, AES, and PKCS5 padding
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from Crypto.Cipher import AES | |
from Crypto import Random | |
BS = 16 | |
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS) | |
unpad = lambda s : s[0:-ord(s[-1])] | |
class AESCipher: | |
def __init__( self, key ): | |
""" | |
Requires hex encoded param as a key | |
""" | |
self.key = key.decode("hex") | |
def encrypt( self, raw ): | |
""" | |
Returns hex encoded encrypted value! | |
""" | |
raw = pad(raw) | |
iv = Random.new().read(AES.block_size); | |
cipher = AES.new( self.key, AES.MODE_CBC, iv ) | |
return ( iv + cipher.encrypt( raw ) ).encode("hex") | |
def decrypt( self, enc ): | |
""" | |
Requires hex encoded param to decrypt | |
""" | |
enc = enc.decode("hex") | |
iv = enc[:16] | |
enc= enc[16:] | |
cipher = AES.new(self.key, AES.MODE_CBC, iv ) | |
return unpad(cipher.decrypt( enc)) | |
if __name__== "__main__": | |
key = "140b41b22a29beb4061bda66b6747e14" | |
ciphertext = "4ca00ff4c898d61e1edbf1800618fb2828a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81"; | |
key=key[:32] | |
decryptor = AESCipher(key) | |
plaintext = decryptor.decrypt(ciphertext) | |
print "%s" % plaintext |
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To anybody else looking for this, the
Crypto.Util.Padding.pad
is now in release 2.7a1. Here's the source: https://github.com/dlitz/pycrypto/blob/master/lib/Crypto/Util/Padding.py