Rearrange the file tree.

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

diff --git a/symm/xtea.h b/symm/xtea.h
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+/* -*-c-*-
+ *
+ * The Extended Tiny Encryption Algorithm
+ *
+ * (c) 2000 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 the Tiny Encryption Algorithm ----------------------------*
+ *
+ * XTEA is an amazingly simple 64-round Feistel network.  It's tiny, fairly
+ * quick and surprisingly strong.  It was invented by David Wheeler and Roger
+ * Needham.  It's unpatented.  XTEA is a new version of TEA, by the same
+ * designers, which fixes some weaknesses in TEA's key schedule.
+ *
+ * This implementation uses big-endian byte order, following SCAN.
+ */
+
+#ifndef CATACOMB_XTEA_H
+#define CATACOMB_XTEA_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stddef.h>
+
+#include <mLib/bits.h>
+
+/*----- Magical numbers ---------------------------------------------------*/
+
+#define XTEA_BLKSZ 8
+#define XTEA_KEYSZ 16
+#define XTEA_CLASS (N, B, 64)
+
+extern const octet xtea_keysz[];
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct xtea_ctx {
+  unsigned r;
+  uint32 k[4];
+} xtea_ctx;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @xtea_init@ --- *
+ *
+ * Arguments:  @xtea_ctx *k@ = pointer to key block
+ *             @const void *buf@ = pointer to key buffer
+ *             @size_t sz@ = size of key material
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes an XTEA key buffer.  The key buffer may be up to
+ *             16 bytes long.
+ */
+
+extern void xtea_init(xtea_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
+
+/* --- @xtea_eblk@, @xtea_dblk@ --- *
+ *
+ * Arguments:  @const xtea_ctx *k@ = pointer to key block
+ *             @const uint32 s[2]@ = pointer to source block
+ *             @uint32 d[2]@ = pointer to xteatination block
+ *
+ * Returns:    ---
+ *
+ * Use:                Low-level block encryption and decryption.
+ */
+
+extern void xtea_eblk(const xtea_ctx */*k*/,
+                     const uint32 */*s*/, uint32 */*d*/);
+extern void xtea_dblk(const xtea_ctx */*k*/,
+                     const uint32 */*s*/, uint32 */*d*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif