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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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4 | * |
5 | * The Data Encryption Standard |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
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18 | * |
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19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
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23 | * |
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24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
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30 | /*----- Notes on the Data Encryption Standard -----------------------------* |
31 | * |
32 | * Almost twenty years after it was first accepted, DES is still the standard |
33 | * block cipher. It's showing its age in its small key size and poor |
34 | * optimiziation for software implementations, but it's not really been badly |
35 | * dented by the intensive analysis thrown at it. |
36 | * |
37 | * This interface is here for compatibility with existing protocols, and |
38 | * because it's a trivial veneer over the base DES code which is used by the |
39 | * @des3@ interface which implements proper strong triple-DES. |
40 | */ |
41 | |
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42 | #ifndef CATACOMB_DES_H |
43 | #define CATACOMB_DES_H |
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44 | |
45 | #ifdef __cplusplus |
46 | extern "C" { |
47 | #endif |
48 | |
49 | /*----- Header files ------------------------------------------------------*/ |
50 | |
51 | #include <stddef.h> |
52 | |
53 | #include <mLib/bits.h> |
54 | |
55 | /*----- Magical numbers ---------------------------------------------------*/ |
56 | |
57 | #define DES_BLKSZ 8 |
58 | #define DES_KEYSZ 7 |
59 | #define DES_CLASS (N, B, 64) |
60 | |
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61 | extern const octet des_keysz[]; |
62 | |
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63 | /*----- Data structures ---------------------------------------------------*/ |
64 | |
65 | typedef struct des_ctx { |
66 | uint32 k[32]; |
67 | } des_ctx; |
68 | |
69 | /*----- Functions provided ------------------------------------------------*/ |
70 | |
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71 | /* --- @des_expand@ --- * |
72 | * |
73 | * Arguments: @const octet *k@ = pointer to key material |
74 | * @size_t n@ = number of octets of key material (7 or 8) |
75 | * @uint32 *xx, *yy@ = where to put the results |
76 | * |
77 | * Returns: --- |
78 | * |
79 | * Use: Extracts 64 bits of key material from the given buffer, |
80 | * possibly expanding it from 56 to 64 bits on the way. |
81 | * Parity is set correctly if the key is expanded. |
82 | */ |
83 | |
84 | extern void des_expand(const octet */*k*/, size_t /*n*/, |
85 | uint32 */*xx*/, uint32 */*yy*/); |
86 | |
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87 | /* --- @des_init@ --- * |
88 | * |
89 | * Arguments: @des_ctx *k@ = pointer to key block |
90 | * @const void *buf@ = pointer to key buffer |
91 | * @size_t sz@ = size of key material |
92 | * |
93 | * Returns: --- |
94 | * |
95 | * Use: Initializes a DES key buffer. The key buffer may be either 7 |
96 | * or 8 bytes long. If it's 8 bytes, the key is assumed to be |
97 | * padded with parity bits in the low order bit of each octet. |
98 | * These are stripped out without checking prior to the actual |
99 | * key scheduling. |
100 | */ |
101 | |
102 | extern void des_init(des_ctx */*k*/, const void */*buf*/, size_t /*sz*/); |
103 | |
104 | /* --- @des_eblk@, @des_dblk@ --- * |
105 | * |
106 | * Arguments: @const des_ctx *k@ = pointer to key block |
107 | * @const uint32 s[2]@ = pointer to source block |
108 | * @uint32 d[2]@ = pointer to destination block |
109 | * |
110 | * Returns: --- |
111 | * |
112 | * Use: Low-level block encryption and decryption. |
113 | */ |
114 | |
115 | extern void des_eblk(const des_ctx */*k*/, |
116 | const uint32 */*s*/, uint32 */*d*/); |
117 | extern void des_dblk(const des_ctx */*k*/, |
118 | const uint32 */*s*/, uint32 */*d*/); |
119 | |
120 | /*----- That's all, folks -------------------------------------------------*/ |
121 | |
122 | #ifdef __cplusplus |
123 | } |
124 | #endif |
125 | |
126 | #endif |