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authorSergey Matveev <stargrave@stargrave.org>2020-07-30 15:57:53 +0300
committerSergey Matveev <stargrave@stargrave.org>2020-07-30 18:31:43 +0300
commit2bb1a163d32e4167e6904ff3c6b4cf64ea7287bb (patch)
tree00d1430a07ed7ff4aad6c86f5345d1b174f4d97d
parent7e5fe8586c0f17834a8df558b7ca86c5d7accd3e (diff)
downloadpygost-2bb1a163d32e4167e6904ff3c6b4cf64ea7287bb.tar.xz
Use curve's cofactor during VKO calculations
-rw-r--r--news.texi2
-rw-r--r--pygost/gost3410.py5
-rw-r--r--pygost/gost3410_vko.py2
-rw-r--r--pygost/stubs/pygost/gost3410.pyi2
4 files changed, 9 insertions, 2 deletions
diff --git a/news.texi b/news.texi
index 4c8094e..5c0442a 100644
--- a/news.texi
+++ b/news.texi
@@ -6,6 +6,8 @@
@anchor{Release 4.9}
@item 4.9
@itemize
+ @item @strong{Fixed} nasty bug with Edwards curves using in
+ 34.10-VKO functions: curve's cofactor has not been used
@item CTR-ACPKM mode of operation
@item OMAC-ACPKM-Master moder of operation
@item KExp15/KImp15 key export/import functions
diff --git a/pygost/gost3410.py b/pygost/gost3410.py
index d7c733d..9f0a11e 100644
--- a/pygost/gost3410.py
+++ b/pygost/gost3410.py
@@ -54,13 +54,14 @@ class GOST3410Curve(object):
:param long e, d: coefficients of the equation of the elliptic curve in
the twisted Edwards form
"""
- def __init__(self, p, q, a, b, x, y, e=None, d=None):
+ def __init__(self, p, q, a, b, x, y, cofactor=1, e=None, d=None):
self.p = p
self.q = q
self.a = a
self.b = b
self.x = x
self.y = y
+ self.cofactor = cofactor
self.e = e
self.d = d
r1 = self.y * self.y % self.p
@@ -165,6 +166,7 @@ CURVES = {
b=bytes2long(hexdec("295F9BAE7428ED9CCC20E7C359A9D41A22FCCD9108E17BF7BA9337A6F8AE9513")),
x=bytes2long(hexdec("91E38443A5E82C0D880923425712B2BB658B9196932E02C78B2582FE742DAA28")),
y=bytes2long(hexdec("32879423AB1A0375895786C4BB46E9565FDE0B5344766740AF268ADB32322E5C")),
+ cofactor=4,
e=0x01,
d=bytes2long(hexdec("0605F6B7C183FA81578BC39CFAD518132B9DF62897009AF7E522C32D6DC7BFFB")),
),
@@ -199,6 +201,7 @@ CURVES = {
b=bytes2long(hexdec("B4C4EE28CEBC6C2C8AC12952CF37F16AC7EFB6A9F69F4B57FFDA2E4F0DE5ADE038CBC2FFF719D2C18DE0284B8BFEF3B52B8CC7A5F5BF0A3C8D2319A5312557E1")),
x=bytes2long(hexdec("E2E31EDFC23DE7BDEBE241CE593EF5DE2295B7A9CBAEF021D385F7074CEA043AA27272A7AE602BF2A7B9033DB9ED3610C6FB85487EAE97AAC5BC7928C1950148")),
y=bytes2long(hexdec("F5CE40D95B5EB899ABBCCFF5911CB8577939804D6527378B8C108C3D2090FF9BE18E2D33E3021ED2EF32D85822423B6304F726AA854BAE07D0396E9A9ADDC40F")),
+ cofactor=4,
e=0x01,
d=bytes2long(hexdec("9E4F5D8C017D8D9F13A5CF3CDF5BFE4DAB402D54198E31EBDE28A0621050439CA6B39E0A515C06B304E2CE43E79E369E91A0CFC2BC2A22B4CA302DBB33EE7550")),
),
diff --git a/pygost/gost3410_vko.py b/pygost/gost3410_vko.py
index 6ffc953..7bc7111 100644
--- a/pygost/gost3410_vko.py
+++ b/pygost/gost3410_vko.py
@@ -34,7 +34,7 @@ def ukm_unmarshal(ukm):
def kek(curve, prv, pub, ukm, mode):
key = curve.exp(prv, pub[0], pub[1])
- key = curve.exp(ukm, key[0], key[1])
+ key = curve.exp(curve.cofactor * ukm, key[0], key[1])
return pub_marshal(key, mode)
diff --git a/pygost/stubs/pygost/gost3410.pyi b/pygost/stubs/pygost/gost3410.pyi
index afab265..4be8b1d 100644
--- a/pygost/stubs/pygost/gost3410.pyi
+++ b/pygost/stubs/pygost/gost3410.pyi
@@ -15,6 +15,7 @@ class GOST3410Curve(object):
b = ... # type: int
x = ... # type: int
y = ... # type: int
+ cofactor = ... # type: int
e = ... # type: int
d = ... # type: int
@@ -26,6 +27,7 @@ class GOST3410Curve(object):
b: int,
x: int,
y: int,
+ cofactor: int = 1,
e: int = None,
d: int = None,
) -> None: ...