Rearrange the file tree.

[u/mdw/catacomb] / symm / cast128.h

diff --git a/symm/cast128.h b/symm/cast128.h
new file mode 100644 (file)
index 0000000..01ba6c6
--- /dev/null
+++ b/symm/cast128.h
@@ -0,0 +1,114 @@
+/* -*-c-*-
+ *
+ * The CAST-128 block cipher
+ *
+ * (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 CAST-128 block cipher --------------------------------*
+ *
+ * CAST, designed by Carlisle Adams and Stafford Tavares, is a method for
+ * designing block ciphers, based around the concept of `bent functions'.  It
+ * is described in the paper `Constructing Symmetric Ciphers using the CAST
+ * Design Procedure' by Carlisle Adams.
+ *
+ * CAST-128, defined in RFC2144, is a particular instance of the CAST design
+ * procedure, The cipher seems strong and fairly quick.  The design procedure
+ * itself is patented, although the cipher CAST-128 is free to use.
+ *
+ * Although CAST ciphers are resistant to differential and linear
+ * cryptanalysis, some instances have been broken by more advanced techniques
+ * -- the CAST procedure does not guarantee a strong cipher.  However,
+ * CAST-128 has so far resisted all attacks against it, and has now been
+ * accepted by the Canadian government for protection of all `Designated'
+ * material.
+ */
+
+#ifndef CATACOMB_CAST128_H
+#define CATACOMB_CAST128_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <mLib/bits.h>
+
+/*----- Magic numbers -----------------------------------------------------*/
+
+#define CAST128_BLKSZ 8
+#define CAST128_KEYSZ 16
+#define CAST128_CLASS (N, B, 64)
+
+extern const octet cast128_keysz[];
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct cast128_ctx {
+  unsigned r;
+  uint32 km[16];
+  octet kr[16];
+} cast128_ctx;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @cast128_init@ --- *
+ *
+ * Arguments:  @cast128_ctx *k@ = pointer to key block to fill in
+ *             @const void *buf@ = pointer to buffer of key material
+ *             @size_t sz@ = size of key material
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes a CAST-128 key buffer.  CAST-128 accepts
+ *             128-bit keys or shorter.
+ */
+
+extern void cast128_init(cast128_ctx */*k*/,
+                        const void */*buf*/, size_t /*sz*/);
+
+/* --- @cast128_eblk@, @cast128_dblk@ --- *
+ *
+ * Arguments:  @const cast128_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 cast128_eblk(const cast128_ctx */*k*/,
+                        const uint32 */*s*/, uint32 */*d*/);
+
+extern void cast128_dblk(const cast128_ctx */*k*/,
+                        const uint32 */*s*/, uint32 */*d*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif