3 * The Data Encryption Standard
5 * (c) 1999 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
12 * Catacomb is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * Catacomb is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with Catacomb; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
28 /*----- Notes on the Data Encryption Standard -----------------------------*
30 * Almost twenty years after it was first accepted, DES is still the standard
31 * block cipher. It's showing its age in its small key size and poor
32 * optimiziation for software implementations, but it's not really been badly
33 * dented by the intensive analysis thrown at it.
35 * This interface is here for compatibility with existing protocols, and
36 * because it's a trivial veneer over the base DES code which is used by the
37 * @des3@ interface which implements proper strong triple-DES.
40 #ifndef CATACOMB_DES_H
41 #define CATACOMB_DES_H
47 /*----- Header files ------------------------------------------------------*/
51 #include <mLib/bits.h>
53 /*----- Magical numbers ---------------------------------------------------*/
57 #define DES_CLASS (N, B, 64)
59 extern const octet des_keysz[];
61 /*----- Data structures ---------------------------------------------------*/
63 typedef struct des_ctx {
67 /*----- Functions provided ------------------------------------------------*/
69 /* --- @des_expand@ --- *
71 * Arguments: @const octet *k@ = pointer to key material
72 * @size_t n@ = number of octets of key material (7 or 8)
73 * @uint32 *xx, *yy@ = where to put the results
77 * Use: Extracts 64 bits of key material from the given buffer,
78 * possibly expanding it from 56 to 64 bits on the way.
79 * Parity is set correctly if the key is expanded.
82 extern void des_expand(const octet */*k*/, size_t /*n*/,
83 uint32 */*xx*/, uint32 */*yy*/);
85 /* --- @des_init@ --- *
87 * Arguments: @des_ctx *k@ = pointer to key block
88 * @const void *buf@ = pointer to key buffer
89 * @size_t sz@ = size of key material
93 * Use: Initializes a DES key buffer. The key buffer may be either 7
94 * or 8 bytes long. If it's 8 bytes, the key is assumed to be
95 * padded with parity bits in the low order bit of each octet.
96 * These are stripped out without checking prior to the actual
100 extern void des_init(des_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
102 /* --- @des_eblk@, @des_dblk@ --- *
104 * Arguments: @const des_ctx *k@ = pointer to key block
105 * @const uint32 s[2]@ = pointer to source block
106 * @uint32 d[2]@ = pointer to destination block
110 * Use: Low-level block encryption and decryption.
113 extern void des_eblk(const des_ctx */*k*/,
114 const uint32 */*s*/, uint32 */*d*/);
115 extern void des_dblk(const des_ctx */*k*/,
116 const uint32 */*s*/, uint32 */*d*/);
118 /*----- That's all, folks -------------------------------------------------*/