X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=pygost%2Ftest_mgm.py;h=e5065d23e8689c2dd8df6133ff5adaf9a9b61d70;hb=b8b853ca49a9dca40f446880fa809af51c611fe0;hp=903415826c7251cc932b4c1bea42c4eb6fbd0919;hpb=7e5fe8586c0f17834a8df558b7ca86c5d7accd3e;p=pygost.git

diff --git a/pygost/test_mgm.py b/pygost/test_mgm.py
index 9034158..e5065d2 100644
--- a/pygost/test_mgm.py
+++ b/pygost/test_mgm.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) 2015-2022 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
@@ -39,7 +39,7 @@ class TestVector(TestCase):
 
 
 class TestSymmetric(TestCase):
-    def _itself(self, mgm, bs):
+    def _itself(self, mgm, bs, tag_size):
         for _ in range(1000):
             nonce = nonce_prepare(urandom(bs))
             ad = urandom(randint(0, 20))
@@ -47,18 +47,29 @@ class TestSymmetric(TestCase):
             if len(ad) + len(pt) == 0:
                 continue
             ct = mgm.seal(nonce, pt, ad)
+            self.assertEqual(len(ct) - tag_size, len(pt))
             self.assertSequenceEqual(mgm.open(nonce, ct, ad), pt)
 
     def test_magma(self):
-        mgm = MGM(
-            GOST3412Magma(urandom(KEYSIZE)).encrypt,
-            GOST3412Magma.blocksize,
-        )
-        self._itself(mgm, GOST3412Magma.blocksize)
+        for tag_size in (
+                GOST3412Magma.blocksize,
+                GOST3412Magma.blocksize - 2,
+        ):
+            mgm = MGM(
+                GOST3412Magma(urandom(KEYSIZE)).encrypt,
+                GOST3412Magma.blocksize,
+                tag_size,
+            )
+            self._itself(mgm, GOST3412Magma.blocksize, tag_size)
 
     def test_kuznechik(self):
-        mgm = MGM(
-            GOST3412Kuznechik(urandom(KEYSIZE)).encrypt,
-            GOST3412Kuznechik.blocksize,
-        )
-        self._itself(mgm, GOST3412Kuznechik.blocksize)
+        for tag_size in (
+                GOST3412Kuznechik.blocksize,
+                GOST3412Kuznechik.blocksize - 2,
+        ):
+            mgm = MGM(
+                GOST3412Kuznechik(urandom(KEYSIZE)).encrypt,
+                GOST3412Kuznechik.blocksize,
+                tag_size,
+            )
+            self._itself(mgm, GOST3412Kuznechik.blocksize, tag_size)