+++ /dev/null
-/* -*-c-*-
- *
- * $Id: rc4.h,v 1.4 2004/04/08 01:36:15 mdw Exp $
- *
- * The alleged RC4 stream cipher
- *
- * (c) 1999 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Notes on RC4 ------------------------------------------------------*
- *
- * RC4 is a stream cipher desgigned by Ron Rivest. For a while RC4 was a
- * trade secret of RSA Data Security, Inc., but somehow source code for a
- * cipher which interworks with RC4 was posted to the Cypherpunks mailing
- * list.
- */
-
-#ifndef CATACOMB_RC4_H
-#define CATACOMB_RC4_H
-
-#ifdef __cplusplus
- extern "C" {
-#endif
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <assert.h>
-
-#include <mLib/bits.h>
-
-#ifndef CATACOMB_GCIPHER_H
-# include "gcipher.h"
-#endif
-
-#ifndef CATACOMB_GRAND_H
-# include "grand.h"
-#endif
-
-/*----- Data structures ---------------------------------------------------*/
-
-typedef struct rc4_ctx {
- unsigned i, j; /* Indices into the @S@ table */
- unsigned f; /* Flags word */
- octet s[256]; /* The ever-changing @S@ table */
-} rc4_ctx;
-
-#define RC4F_OPEN 1u
-
-/*----- Macros ------------------------------------------------------------*/
-
-/* --- @RC4_OPEN@ --- *
- *
- * Arguments: @ctx@ = pointer to an RC4 context
- * @guts@ = code to perform within the RC4 context
- *
- * Use: Performs some code within an RC4 context. Some of the
- * parameters are extracted from the context and held in local
- * variables for speed. Multiple calls to @RC4_BYTE@ may be
- * made within the open context. A context must only be
- * opened once at a time.
- */
-
-#define RC4_OPEN(ctx, guts) do { \
- unsigned _rc4_i = (ctx)->i; \
- unsigned _rc4_j = (ctx)->j; \
- octet *_rc4_s = (ctx)->s; \
- \
- assert(((void)"RC4 context may only be opened once at a time", \
- ((ctx)->f & RC4F_OPEN) == 0)); \
- (ctx)->f |= RC4F_OPEN; \
- \
- guts \
- \
- (ctx)->f &= ~RC4F_OPEN; \
- (ctx)->i = _rc4_i; \
- (ctx)->j = _rc4_j; \
-} while (0)
-
-/* --- @RC4_BYTE@ --- *
- *
- * Arguments: @x@ = output variable to set
- *
- * Use: Extracts an octet from the lexically innermost open RC4
- * context and places it in the variable @x@.
- */
-
-#define RC4_BYTE(x) do { \
- unsigned _si, _sj; \
- _rc4_i = (_rc4_i + 1) & 0xff; \
- _si = _rc4_s[_rc4_i]; \
- _rc4_j = (_rc4_j + _si) & 0xff; \
- _sj = _rc4_s[_rc4_j]; \
- _rc4_s[_rc4_i] = _sj; \
- _rc4_s[_rc4_j] = _si; \
- (x) = _rc4_s[(_si + _sj) & 0xff]; \
-} while (0)
-
-/*----- Functions provided ------------------------------------------------*/
-
-/* --- @rc4_addkey@ --- *
- *
- * Arguments: @rc4_ctx *ctx@ = pointer to context to key
- * @const void *k@ = pointer to key data to use
- * @size_t sz@ = size of the key data
- *
- * Returns: ---
- *
- * Use: Mixes key data with an RC4 context. The RC4 context is not
- * reset before mixing. This may be used to mix new key
- * material with an existing RC4 context.
- */
-
-extern void rc4_addkey(rc4_ctx */*ctx*/, const void */*k*/, size_t /*sz*/);
-
-/* --- @rc4_init@ --- *
- *
- * Arguments: @rc4_ctx *ctx@ = pointer to context to initialize
- * @const void *k@ = pointer to key data to use
- * @size_t sz@ = size of the key data
- *
- * Returns: ---
- *
- * Use: Initializes an RC4 context ready for use.
- */
-
-extern void rc4_init(rc4_ctx */*ctx*/, const void */*k*/, size_t /*sz*/);
-
-/* --- @rc4_encrypt@ --- *
- *
- * Arguments: @rc4_ctx *ctx@ = pointer to context to use
- * @const void *src@ = pointer to the source block
- * @void *dest@ = pointer to the destination block
- * @size_t sz@ = size of the block
- *
- * Returns: ---
- *
- * Use: Encrypts or decrypts a block of data. The destination may
- * be null to just grind the generator around for a while. It's
- * recommended that you say `@rc4_encrypt(&ctx, 0, 0, 1024)@'
- * after initializing a new context, to prevent keystream
- * guessing attacks. The source may be null to just extract a
- * big lump of data from the generator.
- */
-
-extern void rc4_encrypt(rc4_ctx */*ctx*/,
- const void */*src*/, void */*dest*/,
- size_t /*sz*/);
-
-/*----- Generic cipher interface ------------------------------------------*/
-
-#define RC4_KEYSZ 16
-extern const octet rc4_keysz[];
-
-extern const gccipher rc4;
-
-/*----- Generic random number generator interface -------------------------*/
-
-/* --- @rc4_rand@ --- *
- *
- * Arguments: @const void *k@ = pointer to key material
- * @size_t sz@ = size of key material
- *
- * Returns: Pointer to generic random number generator interface.
- *
- * Use: Creates a random number interface wrapper around an
- * OFB-mode block cipher.
- */
-
-extern grand *rc4_rand(const void */*k*/, size_t /*sz*/);
-
-/*----- That's all, folks -------------------------------------------------*/
-
-#ifdef __cplusplus
- }
-#endif
-
-#endif
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