+/* -*-c-*-
+ *
+ * $Id: desx.h,v 1.1 2001/04/03 19:36:50 mdw Exp $
+ *
+ * The DESX algorithm
+ *
+ * (c) 2001 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.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: desx.h,v $
+ * Revision 1.1 2001/04/03 19:36:50 mdw
+ * New block cipher DESX added.
+ *
+ */
+
+/*----- Notes on DESX -----------------------------------------------------*
+ *
+ * DESX was designed by Ron Rivest in 1986 as a simple and cheap way to
+ * strengthen DES against exhaustive search. It also increases the
+ * difficulty of differential and linear attacks.
+ */
+
+#ifndef CATACOMB_DESX_H
+#define CATACOMB_DESX_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stddef.h>
+
+#include <mLib/bits.h>
+
+#ifndef CATACOMB_DES_H
+# include "des.h"
+#endif
+
+/*----- Magical numbers ---------------------------------------------------*/
+
+#define DESX_BLKSZ 8
+#define DESX_KEYSZ 23
+#define DESX_CLASS (N, B, 64)
+
+extern const octet desx_keysz[];
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct desx_ctx {
+ des_ctx k;
+ uint32 prea, preb;
+ uint32 posta, postb;
+} desx_ctx;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @desx_init@ --- *
+ *
+ * Arguments: @desx_ctx *k@ = pointer to key block
+ * @const void *buf@ = pointer to key buffer
+ * @size_t sz@ = size of key material
+ *
+ * Returns: ---
+ *
+ * Use: Initializes a DESX key buffer. The key buffer contains, in
+ * order, an optional 8-byte pre-whitening key, a single-DES key
+ * (either 7 or 8 bytes), and an optional 8-byte port-whitening
+ * key. If no whitening keys are specified, the algorithm
+ * becomes the same as single-DES.
+ */
+
+extern void desx_init(desx_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
+
+/* --- @desx_eblk@, @desx_dblk@ --- *
+ *
+ * Arguments: @const desx_ctx *k@ = pointer to key block
+ * @const uint32 s[2]@ = pointer to source block
+ * @uint32 d[2]@ = pointer to destination block
+ *
+ * Returns: ---
+ *
+ * Use: Low-level block encryption and decryption.
+ */
+
+extern void desx_eblk(const desx_ctx */*k*/,
+ const uint32 */*s*/, uint32 */*d*/);
+extern void desx_dblk(const desx_ctx */*k*/,
+ const uint32 */*s*/, uint32 */*d*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif