Fixed incorrect digest calculation

[pygost.git] / pygost / gost34112012.py

diff --git a/pygost/gost34112012.py b/pygost/gost34112012.py
index 48d7ae2e7bb22185804ab63e0c201d1f7f22a6e0..91782de66365658f6212ee4392e58205fec8b3d1 100644 (file)
--- a/pygost/gost34112012.py
+++ b/pygost/gost34112012.py
@@ -1,6 +1,6 @@
 # coding: utf-8
 # PyGOST -- Pure Python GOST cryptographic functions library
-# Copyright (C) 2015-2022 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2015-2023 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
@@ -268,8 +268,9 @@ class GOST34112012(PEP247):
         """Update state with the new data
         """
         if len(self.buf) > 0:
-            self.buf += data[:BLOCKSIZE - len(self.buf)]
-            data = data[BLOCKSIZE - len(self.buf):]
+            chunk_len = BLOCKSIZE - len(self.buf)
+            self.buf += data[:chunk_len]
+            data = data[chunk_len:]
             if len(self.buf) == BLOCKSIZE:
                 self._update_block(self.buf)
                 self.buf = b""