From kaushalgoa at gmail.com  Tue Jan 11 20:13:37 2011
From: kaushalgoa at gmail.com (Kaushal Bhandankar)
Date: Wed, 12 Jan 2011 00:43:37 +0530
Subject: [python-crypto] Test Vector verification in AES_CTR
Message-ID: <AANLkTimWkp3yEiFOU5QmR_92bcdchkKjNse3cMwbZYE0@mail.gmail.com>

Hi,
An old thread<http://mail.python.org/pipermail/python-crypto/2008-October/001060.html>describes
how to use PyCrypto . However, I am not able to get the desired
ciphered output as per the Test Vectors in SelfTests for AES in AES_CTR
mode. ( lib/Crypto/SelfTest/Cipher/test_AES.py - RFC 3686 test vectors).

Any help would be greatly appreciated.

Thanks,
Kaushal
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From kaushalgoa at gmail.com  Wed Jan 12 06:39:03 2011
From: kaushalgoa at gmail.com (Kaushal Bhandankar)
Date: Wed, 12 Jan 2011 11:09:03 +0530
Subject: [python-crypto] Test Vector verification in AES_CTR
In-Reply-To: <AANLkTimWkp3yEiFOU5QmR_92bcdchkKjNse3cMwbZYE0@mail.gmail.com>
References: <AANLkTimWkp3yEiFOU5QmR_92bcdchkKjNse3cMwbZYE0@mail.gmail.com>
Message-ID: <AANLkTimEfHBMC=5q7+eirtfD-_TaiNZhQu_G7nS8pe9M@mail.gmail.com>

I have figured out that the below code gives the correct ciphered output as
per the Test Vectors in RFC 3686. I have tried this for *"Test Vector
#1"*and I can see that

a) Prefix in counter is concatenated AES-CTR IV and nonce
b) nbits = 32


from Crypto.Cipher import AES
from Crypto.Util import Counter
import binascii

def main():

    plaintext = '53696e676c6520626c6f636b206d7367'
    ctr = Counter.new(nbits=32,
prefix=binascii.a2b_hex('000000300000000000000000'))

    crypto =
AES.new(binascii.a2b_hex('ae6852f8121067cc4bf7a5765577f39e'),AES.MODE_CTR,counter
= ctr)
    encrypted = crypto.encrypt(binascii.a2b_hex(plaintext))
    encrypted_2 = binascii.b2a_hex(encrypted)
    print encrypted_2

if __name__ == "__main__":
    main()

Regards,
Kaushal

On Wed, Jan 12, 2011 at 12:43 AM, Kaushal Bhandankar
<kaushalgoa at gmail.com>wrote:

> Hi,
> An old thread<http://mail.python.org/pipermail/python-crypto/2008-October/001060.html>describes how to use PyCrypto . However, I am not able to get the desired
> ciphered output as per the Test Vectors in SelfTests for AES in AES_CTR
> mode. ( lib/Crypto/SelfTest/Cipher/test_AES.py - RFC 3686 test vectors).
>
> Any help would be greatly appreciated.
>
> Thanks,
> Kaushal
>
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