Rename Kuz to Kuznechik for clarity

[pygost.git] / pygost / gost28147.py

diff --git a/pygost/gost28147.py b/pygost/gost28147.py
index 9b2104747d0f8c3b544dfe75ceb65b52b11d4532..2b39844694a39a8a1a9864e5ea23f25132ef27c9 100644 (file)
--- a/pygost/gost28147.py
+++ b/pygost/gost28147.py
@@ -1,6 +1,6 @@
 # coding: utf-8
 # PyGOST -- Pure Python GOST cryptographic functions library
-# Copyright (C) 2015-2016 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2015-2017 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
@@ -24,11 +24,12 @@ data lengths.
 
 from functools import partial
 
-from pygost.gost3413 import pad1
 from pygost.gost3413 import pad2
+from pygost.gost3413 import pad_size
+from pygost.gost3413 import unpad2
 from pygost.utils import hexdec
 from pygost.utils import strxor
-from pygost.utils import xrange
+from pygost.utils import xrange  # pylint: disable=redefined-builtin
 
 
 KEYSIZE = 32
@@ -347,14 +348,7 @@ def cbc_decrypt(key, data, pad=True, sbox=DEFAULT_SBOX):
             data[i - BLOCKSIZE:i],
         ))
     if pad:
-        last_block = bytearray(plaintext[-1])
-        pad_index = last_block.rfind(b"\x80")
-        if pad_index == -1:
-            raise ValueError("Invalid padding")
-        for c in last_block[pad_index + 1:]:
-            if c != 0:
-                raise ValueError("Invalid padding")
-        plaintext[-1] = bytes(last_block[:pad_index])
+        plaintext[-1] = unpad2(plaintext[-1], BLOCKSIZE)
     return b"".join(plaintext)
 
 
@@ -378,14 +372,12 @@ def cnt(key, data, iv=8 * b"\x00", sbox=DEFAULT_SBOX):
     if not data:
         raise ValueError("No data supplied")
     n2, n1 = encrypt(sbox, key, block2ns(iv))
-    size = len(data)
-    data = pad1(data, BLOCKSIZE)
     gamma = []
-    for _ in xrange(0, len(data), BLOCKSIZE):
+    for _ in xrange(0, len(data) + pad_size(len(data), BLOCKSIZE), BLOCKSIZE):
         n1 = addmod(n1, C2, 2 ** 32)
         n2 = addmod(n2, C1, 2 ** 32 - 1)
         gamma.append(ns2block(encrypt(sbox, key, (n1, n2))))
-    return strxor(b"".join(gamma), data[:size])
+    return strxor(b"".join(gamma), data)
 
 
 MESH_CONST = hexdec("6900722264C904238D3ADB9646E92AC418FEAC9400ED0712C086DCC2EF4CA92B")
@@ -418,10 +410,8 @@ def cfb_encrypt(key, data, iv=8 * b"\x00", sbox=DEFAULT_SBOX, mesh=False):
     validate_sbox(sbox)
     if not data:
         raise ValueError("No data supplied")
-    size = len(data)
-    data = pad1(data, BLOCKSIZE)
     ciphertext = [iv]
-    for i in xrange(0, len(data), BLOCKSIZE):
+    for i in xrange(0, len(data) + pad_size(len(data), BLOCKSIZE), BLOCKSIZE):
         if mesh and i >= MESH_MAX_DATA and i % MESH_MAX_DATA == 0:
             key, iv = meshing(key, ciphertext[-1], sbox=sbox)
             ciphertext.append(strxor(
@@ -433,7 +423,7 @@ def cfb_encrypt(key, data, iv=8 * b"\x00", sbox=DEFAULT_SBOX, mesh=False):
             data[i:i + BLOCKSIZE],
             ns2block(encrypt(sbox, key, block2ns(ciphertext[-1]))),
         ))
-    return b"".join(ciphertext[1:])[:size]
+    return b"".join(ciphertext[1:])
 
 
 def cfb_decrypt(key, data, iv=8 * b"\x00", sbox=DEFAULT_SBOX, mesh=False):
@@ -454,11 +444,9 @@ def cfb_decrypt(key, data, iv=8 * b"\x00", sbox=DEFAULT_SBOX, mesh=False):
     validate_sbox(sbox)
     if not data:
         raise ValueError("No data supplied")
-    size = len(data)
-    data = pad1(data, BLOCKSIZE)
     plaintext = []
     data = iv + data
-    for i in xrange(BLOCKSIZE, len(data), BLOCKSIZE):
+    for i in xrange(BLOCKSIZE, len(data) + pad_size(len(data), BLOCKSIZE), BLOCKSIZE):
         if (
                 mesh and
                 (i - BLOCKSIZE) >= MESH_MAX_DATA and
@@ -474,4 +462,4 @@ def cfb_decrypt(key, data, iv=8 * b"\x00", sbox=DEFAULT_SBOX, mesh=False):
             data[i:i + BLOCKSIZE],
             ns2block(encrypt(sbox, key, block2ns(data[i - BLOCKSIZE:i]))),
         ))
-    return b"".join(plaintext)[:size]
+    return b"".join(plaintext)