X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/6134d9683efd0dd88740a4a7f4804bbb2d92e912..3a65506d4df316377c9b838ef5954b5d856215ee:/rc2.h

diff --git a/rc2.h b/rc2.h
new file mode 100644
index 00000000..5217a331
--- /dev/null
+++ b/rc2.h
@@ -0,0 +1,138 @@
+/* -*-c-*-
+ *
+ * $Id: rc2.h,v 1.1 2000/06/17 11:54:34 mdw Exp $
+ *
+ * The RC2 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.
+ */
+
+/*----- Revision history --------------------------------------------------* 
+ *
+ * $Log: rc2.h,v $
+ * Revision 1.1  2000/06/17 11:54:34  mdw
+ * New cipher.
+ *
+ */
+
+/*----- Notes on the RC2 block cipher -------------------------------------*
+ *
+ * RC2 was designed by Ron Rivest, and for a long time was a trade secret of
+ * RSA Data Security Inc.  Like RC4, it leaked out, and has now been
+ * described in RFC2268.  The RC2 key schedule is known to have some
+ * weaknesses, although I'm not aware of any major results against the cipher
+ * itself.  I'm also not aware of any legal problems with using the RC2
+ * cipher.
+ *
+ * The oddest feature in the cipher is the key schedule.  It expands the
+ * initial key material to 128 bytes, and then `brain-damages' it, according
+ * to a supplied `effective key-bits' parameter, before expanding the
+ * remaining key material back into the buffer.
+ *
+ * The key schedule allows second preimages to be computed trivially.
+ */
+
+#ifndef CATACOMB_RC2_H
+#define CATACOMB_RC2_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stddef.h>
+
+#include <mLib/bits.h>
+
+/*----- Magical numbers ---------------------------------------------------*/
+
+#define RC2_BLKSZ 8
+#define RC2_KEYSZ 16
+#define RC2_CLASS (N, L, 64)
+
+extern const octet rc2_keysz[];
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct rc2_ctx {
+  uint16 k[64];
+} rc2_ctx;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @rc2_braindamage@ --- *
+ *
+ * Arguments:	@rc2_ctx *k@ = pointer to context to initialize
+ *		@const void *buf@ = pointer to key material
+ *		@size_t sz@ = size of key material in bytes
+ *		@unsigned eb@ = desired effective key size, in bits
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes an RC2 expanded key, and braindamages it to the
+ *		requested effective key size.  This is here for compatibility
+ *		reasons.  You should be using @rc2_init@ in normal code,
+ *		which doesn't actually apply braindamage.
+ */
+
+extern void rc2_braindamage(rc2_ctx */*k*/, const void */*buf*/,
+			    size_t /*sz*/, unsigned /*eb*/);
+
+/* --- @rc2_init@ --- *
+ *
+ * Arguments:	@rc2_ctx *k@ = pointer to context to initialize
+ *		@const void *buf@ = pointer to key material
+ *		@size_t sz@ = size of key material in bytes
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes an RC2 expanded key.  The effective key size is
+ *		set to be equal to the real key size, in bits.
+ */
+
+extern void rc2_init(rc2_ctx */*k*/, const void */*buf*/, size_t /*sz*/);
+
+/* --- @rc2_eblk@, @rc2_dblk@ --- *
+ *
+ * Arguments:	@const rc2_ctx *k@ = pointer to RC2 context
+ *		@const uint32 s[2]@ = pointer to source block
+ *		@const uint32 d[2]@ = pointer to destination block
+ *
+ * Returns:	---
+ *
+ * Use:		Low-level block encryption and decryption.
+ */
+
+extern void rc2_eblk(const rc2_ctx */*k*/,
+		     const uint32 */*s*/, uint32 */*dst*/);
+extern void rc2_dblk(const rc2_ctx */*k*/,
+		     const uint32 */*s*/, uint32 */*dst*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif