X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=pygost%2Fgost3410_vko.py;h=f72a136fe94b41c8a28ee9555f9058687b1d3c89;hb=fbaa1fc82dbec2c3ebaf8d272600ef4f91649e08;hp=6ffc9537014f0b570399fed4d3042fa7708530d1;hpb=c36d50a5003f360ff22f93e286efd0f614523427;p=pygost.git

diff --git a/pygost/gost3410_vko.py b/pygost/gost3410_vko.py
index 6ffc953..f72a136 100644
--- a/pygost/gost3410_vko.py
+++ b/pygost/gost3410_vko.py
@@ -1,6 +1,6 @@
 # coding: utf-8
 # PyGOST -- Pure Python GOST cryptographic functions library
-# Copyright (C) 2015-2020 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2015-2024 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
@@ -32,14 +32,18 @@ def ukm_unmarshal(ukm):
     return bytes2long(ukm[::-1])
 
 
-def kek(curve, prv, pub, ukm, mode):
+def kek(curve, prv, pub, ukm, mask=None):
+    if not curve.contains(pub):
+        raise ValueError("pub is not on the curve")
     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])
+    if mask is not None:
+        key = curve.exp(mask, key[0], key[1])
+    return pub_marshal(key)
 
 
 def kek_34102001(curve, prv, pub, ukm):
-    """ Key agreement (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
@@ -54,13 +58,13 @@ def kek_34102001(curve, prv, pub, ukm):
     hash output.
     """
     return GOST341194(
-        kek(curve, prv, pub, ukm, mode=2001),
+        kek(curve, prv, pub, ukm),
         sbox="id-GostR3411-94-CryptoProParamSet",
     ).digest()
 
 
-def kek_34102012256(curve, prv, pub, ukm=1, mode=2012):
-    """ Key agreement (34.10-2012, 34.11-2012 256 bit)
+def kek_34102012256(curve, prv, pub, ukm=1):
+    """Key agreement (34.10-2012, 34.11-2012 256 bit)
 
     :param GOST3410Curve curve: curve to use
     :param long prv: private key
@@ -73,11 +77,11 @@ def kek_34102012256(curve, prv, pub, ukm=1, mode=2012):
     Shared Key Encryption Key computation is based on
     :rfc:`7836` VKO GOST R 34.10-2012.
     """
-    return GOST34112012256(kek(curve, prv, pub, ukm, mode=mode)).digest()
+    return GOST34112012256(kek(curve, prv, pub, ukm)).digest()
 
 
 def kek_34102012512(curve, prv, pub, ukm=1):
-    """ Key agreement (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
@@ -90,4 +94,4 @@ def kek_34102012512(curve, prv, pub, ukm=1):
     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()