X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=pygost%2Fgost3410_vko.py;h=4bc2d4e9df85410c7d21d6f7ab88999e1a95b25d;hb=82af8726ef5d5e2752089a45750e56c9910398c7;hp=caf3b5bd2585d8e1dae25511045a19fc1f4c72ca;hpb=8ed245158dd501fd5f4a161eeb5007e6d0f8050b;p=pygost.git

diff --git a/pygost/gost3410_vko.py b/pygost/gost3410_vko.py
index caf3b5b..4bc2d4e 100644
--- a/pygost/gost3410_vko.py
+++ b/pygost/gost3410_vko.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
@@ -14,7 +13,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
-"""Diffie-Hellman functions, VKO GOST R 34.10-2001/2012
+"""Key agreement functions, VKO GOST R 34.10-2001/2012
 """
 
 from pygost.gost3410 import pub_marshal
@@ -27,20 +26,20 @@ from pygost.utils import bytes2long
 def ukm_unmarshal(ukm):
     """Unmarshal UKM value
 
-    :type ukm: bytes
+    :type ukm: little-endian bytes
     :rtype: long
     """
     return bytes2long(ukm[::-1])
 
 
-def kek(curve, prv, pub, ukm, mode):
+def kek(curve, prv, pub, ukm):
     key = curve.exp(prv, pub[0], pub[1])
-    key = curve.exp(ukm, key[0], key[1])
-    return pub_marshal(key, mode)
+    key = curve.exp(curve.cofactor * ukm, key[0], key[1])
+    return pub_marshal(key)
 
 
 def kek_34102001(curve, prv, pub, ukm):
-    """ Make Diffie-Hellman computation (34.10-2001, 34.11-94)
+    """ Key agreement (34.10-2001, 34.11-94)
 
     :param GOST3410Curve curve: curve to use
     :param long prv: private key
@@ -55,13 +54,13 @@ def kek_34102001(curve, prv, pub, ukm):
     hash output.
     """
     return GOST341194(
-        kek(curve, prv, pub, ukm, mode=2001),
-        "GostR3411_94_CryptoProParamSet",
+        kek(curve, prv, pub, ukm),
+        sbox="id-GostR3411-94-CryptoProParamSet",
     ).digest()
 
 
 def kek_34102012256(curve, prv, pub, ukm=1):
-    """ Make Diffie-Hellman computation (34.10-2012, 34.11-2012 256 bit)
+    """ Key agreement (34.10-2012, 34.11-2012 256 bit)
 
     :param GOST3410Curve curve: curve to use
     :param long prv: private key
@@ -70,12 +69,15 @@ def kek_34102012256(curve, prv, pub, ukm=1):
     :param long ukm: user keying material, VKO-factor
     :returns: Key Encryption Key (shared key)
     :rtype: bytes, 32 bytes
+
+    Shared Key Encryption Key computation is based on
+    :rfc:`7836` VKO GOST R 34.10-2012.
     """
-    return GOST34112012256(kek(curve, prv, pub, ukm, mode=2012)).digest()
+    return GOST34112012256(kek(curve, prv, pub, ukm)).digest()
 
 
 def kek_34102012512(curve, prv, pub, ukm=1):
-    """ Make Diffie-Hellman computation (34.10-2012, 34.11-2012 512 bit)
+    """ Key agreement (34.10-2012, 34.11-2012 512 bit)
 
     :param GOST3410Curve curve: curve to use
     :param long prv: private key
@@ -84,5 +86,8 @@ def kek_34102012512(curve, prv, pub, ukm=1):
     :param long ukm: user keying material, VKO-factor
     :returns: Key Encryption Key (shared key)
     :rtype: bytes, 32 bytes
+
+    Shared Key Encryption Key computation is based on
+    :rfc:`7836` VKO GOST R 34.10-2012.
     """
-    return GOST34112012512(kek(curve, prv, pub, ukm, mode=2012)).digest()
+    return GOST34112012512(kek(curve, prv, pub, ukm)).digest()