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Add nonce and initial_value parameters to CTR mode

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This commit is contained in:
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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10
lib/Crypto/Cipher/_mode_siv.py
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@ -36,9 +36,8 @@ __all__ = ['SivMode']
from binascii import hexlify
from Crypto.Util.py3compat import byte_string, bord, unhexlify
from Crypto.Util.py3compat import byte_string, bord, unhexlify, b
from Crypto.Util import Counter
from Crypto.Util.number import long_to_bytes, bytes_to_long
from Crypto.Protocol.KDF import _S2V
from Crypto.Hash import BLAKE2s
@ -125,14 +124,11 @@ class SivMode(object):
"""Create a new CTR cipher from the MAC in SIV mode"""
tag_int = bytes_to_long(mac_tag)
init_counter = tag_int ^ (tag_int & 0x8000000080000000L)
ctr = Counter.new(self.block_size * 8,
initial_value=init_counter)
return self._factory.new(
self._subkey_cipher,
self._factory.MODE_CTR,
counter=ctr,
initial_value=tag_int ^ (tag_int & 0x8000000080000000L),
nonce=b(""),
**self._cipher_params)
def update(self, component):