3 * $Id: rc2.h,v 1.1 2000/06/17 11:54:34 mdw Exp $
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.1 2000/06/17 11:54:34 mdw
38 /*----- Notes on the RC2 block cipher -------------------------------------*
40 * RC2 was designed by Ron Rivest, and for a long time was a trade secret of
41 * RSA Data Security Inc. Like RC4, it leaked out, and has now been
42 * described in RFC2268. The RC2 key schedule is known to have some
43 * weaknesses, although I'm not aware of any major results against the cipher
44 * itself. I'm also not aware of any legal problems with using the RC2
47 * The oddest feature in the cipher is the key schedule. It expands the
48 * initial key material to 128 bytes, and then `brain-damages' it, according
49 * to a supplied `effective key-bits' parameter, before expanding the
50 * remaining key material back into the buffer.
52 * The key schedule allows second preimages to be computed trivially.
55 #ifndef CATACOMB_RC2_H
56 #define CATACOMB_RC2_H
62 /*----- Header files ------------------------------------------------------*/
66 #include <mLib/bits.h>
68 /*----- Magical numbers ---------------------------------------------------*/
72 #define RC2_CLASS (N, L, 64)
74 extern const octet rc2_keysz
[];
76 /*----- Data structures ---------------------------------------------------*/
78 typedef struct rc2_ctx
{
82 /*----- Functions provided ------------------------------------------------*/
84 /* --- @rc2_braindamage@ --- *
86 * Arguments: @rc2_ctx *k@ = pointer to context to initialize
87 * @const void *buf@ = pointer to key material
88 * @size_t sz@ = size of key material in bytes
89 * @unsigned eb@ = desired effective key size, in bits
93 * Use: Initializes an RC2 expanded key, and braindamages it to the
94 * requested effective key size. This is here for compatibility
95 * reasons. You should be using @rc2_init@ in normal code,
96 * which doesn't actually apply braindamage.
99 extern void rc2_braindamage(rc2_ctx */
*k*/
, const void */
*buf*/
,
100 size_t /*sz*/, unsigned /*eb*/);
102 /* --- @rc2_init@ --- *
104 * Arguments: @rc2_ctx *k@ = pointer to context to initialize
105 * @const void *buf@ = pointer to key material
106 * @size_t sz@ = size of key material in bytes
110 * Use: Initializes an RC2 expanded key. The effective key size is
111 * set to be equal to the real key size, in bits.
114 extern void rc2_init(rc2_ctx */
*k*/
, const void */
*buf*/
, size_t /*sz*/);
116 /* --- @rc2_eblk@, @rc2_dblk@ --- *
118 * Arguments: @const rc2_ctx *k@ = pointer to RC2 context
119 * @const uint32 s[2]@ = pointer to source block
120 * @const uint32 d[2]@ = pointer to destination block
124 * Use: Low-level block encryption and decryption.
127 extern void rc2_eblk(const rc2_ctx */
*k*/
,
128 const uint32 */
*s*/
, uint32 */
*dst*/
);
129 extern void rc2_dblk(const rc2_ctx */
*k*/
,
130 const uint32 */
*s*/
, uint32 */
*dst*/
);
132 /*----- That's all, folks -------------------------------------------------*/