Rearrange the file tree.

[u/mdw/catacomb] / symm / desx.h

diff --git a/symm/desx.h b/symm/desx.h
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+/* -*-c-*-
+ *
+ * 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.
+ */
+
+/*----- 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