# coding: utf-8
# PyGOST -- Pure Python GOST cryptographic functions library
-# Copyright (C) 2015-2020 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2015-2021 Sergey Matveev <stargrave@stargrave.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
-""" GOST R 34.11-2012 (Streebog) hash function common files
+"""GOST R 34.11-2012 (Streebog) hash function common files
This is implementation of :rfc:`6986`. Most function and variable names are
taken according to specification's terminology.
)]
+def _lcache():
+ cache = []
+ for byteN in xrange(8):
+ cache.append([0 for _ in xrange(256)])
+ for byteN in xrange(8):
+ for byteVal in xrange(256):
+ res64 = 0
+ val = byteVal
+ for bitN in xrange(8):
+ if val & 0x80 > 0:
+ res64 ^= A[(7 - byteN) * 8 + bitN]
+ val <<= 1
+ cache[byteN][byteVal] = res64
+ return cache
+
+
+# Trade memory for CPU for part of L() calculations
+LCache = _lcache()
+
+
def add512bit(a, b):
- """ Add two 512 integers
+ """Add two 512 integers
"""
a = bytearray(a)
b = bytearray(b)
def L(data):
res = []
for i in range(8):
- val = unpack("<Q", data[i * 8:i * 8 + 8])[0]
res64 = 0
- for j in range(BLOCKSIZE):
- if val & 0x8000000000000000:
- res64 ^= A[j]
- val <<= 1
+ for j in range(8):
+ res64 ^= LCache[j][data[8 * i + j]]
res.append(pack("<Q", res64))
return b"".join(res)
class GOST34112012(PEP247):
- """ GOST 34.11-2012 big-endian hash
+ """GOST 34.11-2012 big-endian hash
>>> m = GOST34112012(digest_size=32)
>>> m.update("foo")
return self._digest_size
def update(self, data):
- """ Append data that has to be hashed
+ """Append data that has to be hashed
"""
self.data += data
def digest(self):
- """ Get hash of the provided data
+ """Get hash of the provided data
"""
hsh = BLOCKSIZE * (b"\x01" if self.digest_size == 32 else b"\x00")
chk = bytearray(BLOCKSIZE * b"\x00")