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[pygost.git] / pygost / gost341194.py

diff --git a/pygost/gost341194.py b/pygost/gost341194.py
index adc0925f6e53e32cbbb909dfc978f9b08dd87530..c27662851ccfbd29b609368ba1bcab29224195ce 100644 (file)
--- a/pygost/gost341194.py
+++ b/pygost/gost341194.py
@@ -1,6 +1,6 @@
 # coding: utf-8
 # PyGOST -- Pure Python GOST cryptographic functions library
-# Copyright (C) 2015-2016 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2015-2018 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
@@ -29,10 +29,12 @@ 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.utils import hexdec
 from pygost.utils import hexenc
+from pygost.utils import long2bytes
 from pygost.utils import strxor
-from pygost.utils import xrange
+from pygost.utils import xrange  # pylint: disable=redefined-builtin
 
 
 DEFAULT_SBOX = "GostR3411_94_TestParamSet"
@@ -159,18 +161,18 @@ 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
+            _len += len(part) * 8
             checksum = addmod(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:
@@ -183,3 +185,36 @@ class GOST341194(PEP247):
 
 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
+
+    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]