summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSergey Matveev <stargrave@stargrave.org>2017-12-24 13:18:28 +0300
committerSergey Matveev <stargrave@stargrave.org>2018-12-09 13:00:17 +0300
commit22d0a1d34cbf1466e01b59a8567af36cf315f328 (patch)
tree5ae346b4ebd475e3ff7c87dc7438cd991d429372
parent8041023f83244e7bc19c9bb02ae8ba83ffdf654b (diff)
downloadpygost-22d0a1d34cbf1466e01b59a8567af36cf315f328.tar.xz
Fix 34.13 OFB bug with len(IV) > 2
-rw-r--r--pygost/gost3413.py2
-rw-r--r--pygost/test_gost3413.py14
2 files changed, 15 insertions, 1 deletions
diff --git a/pygost/gost3413.py b/pygost/gost3413.py
index c0201c9..cdf8210 100644
--- a/pygost/gost3413.py
+++ b/pygost/gost3413.py
@@ -138,7 +138,7 @@ def ofb(encrypter, bs, data, iv):
result = []
for i in xrange(0, len(data) + pad_size(len(data), bs), bs):
r = r[1:] + [encrypter(r[0])]
- result.append(strxor(r[1], data[i:i + bs]))
+ result.append(strxor(r[-1], data[i:i + bs]))
return b"".join(result)
diff --git a/pygost/test_gost3413.py b/pygost/test_gost3413.py
index f1574ee..e26a3ea 100644
--- a/pygost/test_gost3413.py
+++ b/pygost/test_gost3413.py
@@ -18,6 +18,7 @@ from pygost.gost3413 import pad2
from pygost.gost3413 import unpad2
from pygost.utils import hexdec
from pygost.utils import hexenc
+from pygost.utils import strxor
class Pad2Test(TestCase):
@@ -110,6 +111,19 @@ class GOST3412KuznechikModesTest(TestCase):
ct = ofb(ciph.encrypt, 16, pt, iv)
self.assertSequenceEqual(ofb(ciph.encrypt, 16, ct, iv), pt)
+ def test_ofb_manual(self):
+ iv = [urandom(16) for _ in range(randint(2, 10))]
+ pt = [urandom(16) for _ in range(len(iv), len(iv) + randint(1, 10))]
+ ciph = GOST3412Kuznechik(urandom(32))
+ r = [ciph.encrypt(i) for i in iv]
+ for i in range(len(pt) - len(iv)):
+ r.append(ciph.encrypt(r[i]))
+ ct = [strxor(g, r) for g, r in zip(pt, r)]
+ self.assertSequenceEqual(
+ ofb(ciph.encrypt, 16, b"".join(pt), b"".join(iv)),
+ b"".join(ct),
+ )
+
def test_cbc_vectors(self):
ciphtext = ""
ciphtext += "689972d4a085fa4d90e52e3d6d7dcc27"