Completely get rid of addmod

[pygost.git] / pygost / gost341194.py

diff --git a/pygost/gost341194.py b/pygost/gost341194.py
index 0a71518cb445d6c733eb2b24237dcb8409d3420c..4ffb45e63f189cb4a4c1027b884c68ee54fddf6e 100644 (file)
--- a/pygost/gost341194.py
+++ b/pygost/gost341194.py
@@ -1,11 +1,10 @@
 # coding: utf-8
 # PyGOST -- Pure Python GOST cryptographic functions library
-# Copyright (C) 2015-2016 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2015-2020 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
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
+# the Free Software Foundation, version 3 of the License.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -21,23 +20,22 @@ taken according to specification's terminology.
 """
 
 from copy import copy
+from functools import partial
 from struct import pack
 
-from pygost.gost28147 import addmod
 from pygost.gost28147 import block2ns
 from pygost.gost28147 import encrypt
 from pygost.gost28147 import ns2block
 from pygost.gost28147 import validate_sbox
 from pygost.iface import PEP247
-from pygost.utils import bytes2long
+from pygost.pbkdf2 import pbkdf2 as pbkdf2_base
 from pygost.utils import hexdec
 from pygost.utils import hexenc
-from pygost.utils import long2bytes
 from pygost.utils import strxor
 from pygost.utils import xrange
 
 
-DEFAULT_SBOX = "GostR3411_94_TestParamSet"
+DEFAULT_SBOX = "id-GostR3411-94-CryptoProParamSet"
 BLOCKSIZE = 32
 C2 = 32 * b"\x00"
 C3 = hexdec(b"ff00ffff000000ffff0000ff00ffff0000ff00ff00ff00ffff00ff00ff00ff00")
@@ -161,18 +159,18 @@ class GOST341194(PEP247):
     def digest(self):
         """ Get hash of the provided data
         """
-        l = 0
+        _len = 0
         checksum = 0
         h = 32 * b"\x00"
         m = self.data
         for i in xrange(0, len(m), BLOCKSIZE):
             part = m[i:i + BLOCKSIZE][::-1]
-            l += len(part) * 8
-            checksum = addmod(checksum, int(hexenc(part), 16), 2 ** 256)
+            _len += len(part) * 8
+            checksum = (checksum + int(hexenc(part), 16)) % (2 ** 256)
             if len(part) < BLOCKSIZE:
                 part = b"\x00" * (BLOCKSIZE - len(part)) + part
             h = _step(h, part, self.sbox)
-        h = _step(h, 24 * b"\x00" + pack(">Q", l), self.sbox)
+        h = _step(h, 24 * b"\x00" + pack(">Q", _len), self.sbox)
 
         checksum = hex(checksum)[2:].rstrip("L")
         if len(checksum) % 2 != 0:
@@ -187,34 +185,8 @@ def new(data=b"", sbox=DEFAULT_SBOX):
     return GOST341194(data, sbox)
 
 
-# This implementation is based on Python 3.5.2 source code's one.
-# PyGOST does not register itself in hashlib anyway, so use it instead.
-def pbkdf2(password, salt, iterations, dklen):
-    """PBKDF2 implementation for GOST R 34.11-94
+PBKDF2_HASHER = partial(GOST341194, sbox="id-GostR3411-94-CryptoProParamSet")
 
-    Based on http://tc26.ru/methods/containers_v1/Addition_to_PKCS5_v1_0.pdf
-    """
-    inner = GOST341194(sbox="GostR3411_94_CryptoProParamSet")
-    outer = GOST341194(sbox="GostR3411_94_CryptoProParamSet")
-    password = password + b"\x00" * (inner.block_size - len(password))
-    inner.update(strxor(password, len(password) * b"\x36"))
-    outer.update(strxor(password, len(password) * b"\x5C"))
-
-    def prf(msg):
-        icpy = inner.copy()
-        ocpy = outer.copy()
-        icpy.update(msg)
-        ocpy.update(icpy.digest())
-        return ocpy.digest()
-
-    dkey = b''
-    loop = 1
-    while len(dkey) < dklen:
-        prev = prf(salt + long2bytes(loop, 4))
-        rkey = bytes2long(prev)
-        for _ in xrange(iterations - 1):
-            prev = prf(prev)
-            rkey ^= bytes2long(prev)
-        loop += 1
-        dkey += long2bytes(rkey, inner.digest_size)
-    return dkey[:dklen]
+
+def pbkdf2(password, salt, iterations, dklen):
+    return pbkdf2_base(PBKDF2_HASHER, password, salt, iterations, dklen)