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comparison dcrypt/crypto/padding/PKCS7.d @ 0:0e08791a1418

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Initial import.
author Thomas Dixon <reikon@reikon.us>
date Sun, 10 Aug 2008 14:20:17 -0400
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children cd376996cdb3
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-1:000000000000 0:0e08791a1418
1 /**
2 * This file is part of the dcrypt project.
3 *
4 * Copyright: Copyright (C) dcrypt contributors 2008. All rights reserved.
5 * License: MIT
6 * Authors: Thomas Dixon
7 */
8
9 module dcrypt.crypto.padding.PKCS7;
10
11 import dcrypt.crypto.BlockCipherPadding;
12
13 /**
14 * This class implements the padding scheme described in PKCS7
15 * from RSA Security. Ex. [... 0x03, 0x03, 0x03]
16 */
17 class PKCS7 : BlockCipherPadding {
18 char[] name() {
19 return "PKCS7";
20 }
21
22 /* Assumes input_ is a multiple of the underlying
23 * block cipher's block size.
24 */
25 uint padBlock(void[] input_, uint inOff) {
26 ubyte[] input = cast(ubyte[]) input_;
27
28 ubyte len = (input.length - inOff);
29
30 input[inOff..input.length] = len;
31
32 return len;
33 }
34
35 uint padLength(void[] input_) {
36 ubyte[] input = cast(ubyte[]) input_;
37
38 ubyte len = input[input.length-1];
39
40 if (len > input.length || len == 0)
41 throw new InvalidPaddingError(name()~": Incorrect padding.");
42
43 uint limit = input.length;
44 for (int i = 0; i < len; i++)
45 if (input[--limit] != len)
46 throw new InvalidPaddingError(
47 name()~": Pad value does not match pad length.");
48 return len;
49 }
50 }