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Add nonce and initial_value parameters to CTR mode

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Legrandin 2015-12-20 21:27:21 +01:00
parent 6fc0c734a2
commit c74b718aa6
13 changed files with 210 additions and 71 deletions
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5
lib/Crypto/Cipher/_mode_ccm.py
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@ -36,7 +36,6 @@ __all__ = ['CcmMode']
from Crypto.Util.py3compat import byte_string, b, bchr, bord, unhexlify
from Crypto.Util import Counter
from Crypto.Util.strxor import strxor
from Crypto.Util.number import long_to_bytes
@ -163,11 +162,9 @@ class CcmMode(object):
# Start CTR cipher, by formatting the counter (A.3)
q = 15 - len(nonce) # length of Q, the encoded message length
prefix = bchr(q - 1) + nonce
ctr = Counter.new(128 - len(prefix) * 8, prefix, initial_value=0)
self._cipher = self._factory.new(key,
self._factory.MODE_CTR,
counter=ctr,
nonce=bchr(q - 1) + nonce,
**cipher_params)
# S_0, step 6 in 6.1 for j=0