X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/symm/cbc.h

diff --git a/symm/cbc.h b/symm/cbc.h
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+/* -*-c-*-
+ *
+ * Ciphertext block chaining for block ciphers
+ *
+ * (c) 1999 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.
+ */
+
+#ifndef CATACOMB_CBC_H
+#define CATACOMB_CBC_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stddef.h>
+
+#include <mLib/bits.h>
+
+#ifndef CATACOMB_GCIPHER_H
+#  include "gcipher.h"
+#endif
+
+/*----- Macros ------------------------------------------------------------*/
+
+/* --- @CBC_DECL@ --- *
+ *
+ * Arguments:	@PRE@, @pre@ = prefixes for the underlying block cipher
+ *
+ * Use:		Creates declarations for CBC stealing mode.
+ */
+
+#define CBC_DECL(PRE, pre)						\
+									\
+/* --- Cipher block chaining context --- */				\
+									\
+typedef struct pre##_cbcctx {						\
+  pre##_ctx ctx;			/* Underlying cipher context */	\
+  uint32 iv[PRE##_BLKSZ / 4];		/* Previous ciphertext or IV */	\
+} pre##_cbcctx;								\
+									\
+/* --- @pre_cbcgetiv@ --- *						\
+ *									\
+ * Arguments:	@const pre_cbcctx *ctx@ = pointer to CBC context block	\
+ *		@void *iv@ = pointer to output data block		\
+ *									\
+ * Returns:	---							\
+ *									\
+ * Use:		Reads the currently set IV.  Reading and setting an IV	\
+ *		is transparent to the CBC encryption or decryption	\
+ *		process.						\
+ */									\
+									\
+extern void pre##_cbcgetiv(const pre##_cbcctx */*ctx*/,			\
+			   void */*iv*/);				\
+									\
+/* --- @pre_cbcsetiv@ --- *						\
+ *									\
+ * Arguments:	@pre_cbcctx *ctx@ = pointer to CBC context block	\
+ *		@cnost void *iv@ = pointer to IV to set			\
+ *									\
+ * Returns:	---							\
+ *									\
+ * Use:		Sets the IV to use for subsequent encryption.		\
+ */									\
+									\
+extern void pre##_cbcsetiv(pre##_cbcctx */*ctx*/,			\
+			   const void */*iv*/);				\
+									\
+/* --- @pre_cbcsetkey@ --- *						\
+ *									\
+ * Arguments:	@pre_cbcctx *ctx@ = pointer to CBC context block	\
+ *		@const pre_ctx *k@ = pointer to cipher context		\
+ *									\
+ * Returns:	---							\
+ *									\
+ * Use:		Sets the CBC context to use a different cipher key.	\
+ */									\
+									\
+extern void pre##_cbcsetkey(pre##_cbcctx */*ctx*/,			\
+			    const pre##_ctx */*k*/);			\
+									\
+/* --- @pre_cbcinit@ --- *						\
+ *									\
+ * Arguments:	@pre_cbcctx *ctx@ = pointer to cipher context		\
+ *		@const void *key@ = pointer to the key buffer		\
+ *		@size_t sz@ = size of the key				\
+ *		@const void *iv@ = pointer to initialization vector	\
+ *									\
+ * Returns:	---							\
+ *									\
+ * Use:		Initializes a CBC context ready for use.  The @iv@	\
+ *		argument may be passed as a null pointer to set a zero	\
+ *		IV.  Apart from that, this call is equivalent to calls	\
+ *		to @pre_init@, @pre_cbcsetkey@ and @pre_cbcsetiv@.	\
+ */									\
+									\
+extern void pre##_cbcinit(pre##_cbcctx */*ctx*/,			\
+			  const void */*key*/, size_t /*sz*/,		\
+			  const void */*iv*/);				\
+									\
+/* --- @pre_cbcencrypt@ --- *						\
+ *									\
+ * Arguments:	@pre_cbcctx *ctx@ = pointer to CBC context block	\
+ *		@const void *src@ = pointer to source data		\
+ *		@void *dest@ = pointer to destination data		\
+ *		@size_t sz@ = size of block to be encrypted		\
+ *									\
+ * Returns:	---							\
+ *									\
+ * Use:		Encrypts a block with a block cipher in CBC mode, with	\
+ *		ciphertext stealing and other clever tricks.		\
+ *		Essentially, data can be encrypted in arbitrary sized	\
+ *		chunks, although decryption must use the same chunks.	\
+ */									\
+									\
+extern void pre##_cbcencrypt(pre##_cbcctx */*ctx*/,			\
+			     const void */*src*/, void */*dest*/,	\
+			     size_t /*sz*/);				\
+									\
+/* --- @pre_cbcdecrypt@ --- *						\
+ *									\
+ * Arguments:	@pre_cbcctx *ctx@ = pointer to CBC context block	\
+ *		@const void *src@ = pointer to source data		\
+ *		@void *dest@ = pointer to destination data		\
+ *		@size_t sz@ = size of block to be encrypted		\
+ *									\
+ * Returns:	---							\
+ *									\
+ * Use:		Decrypts a block with a block cipher in CBC mode, with	\
+ *		ciphertext stealing and other clever tricks.		\
+ *		Essentially, data can be encrypted in arbitrary sized	\
+ *		chunks, although decryption must use the same chunks.	\
+ */									\
+									\
+extern void pre##_cbcdecrypt(pre##_cbcctx */*ctx*/,			\
+			     const void */*src*/, void */*dest*/,	\
+			     size_t /*sz*/);				\
+									\
+/* --- Generic cipher interface --- */					\
+									\
+extern const gccipher pre##_cbc;
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif