Added support for MD2 hash function.

[u/mdw/catacomb] / md2.h

diff --git a/md2.h b/md2.h
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+/* -*-c-*-
+ *
+ * $Id: md2.h,v 1.1 2001/02/21 20:03:22 mdw Exp $
+ *
+ * The MD2 message digest function
+ *
+ * (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.
+ */
+
+/*----- Revision history --------------------------------------------------* 
+ *
+ * $Log: md2.h,v $
+ * Revision 1.1  2001/02/21 20:03:22  mdw
+ * Added support for MD2 hash function.
+ *
+ */
+
+/*----- Notes on the MD2 hash function ------------------------------------*
+ *
+ * MD2 was designed by Ron Rivest.  It's not recommended for new applications
+ * because only the `checksum' part of the function resists collision-finding
+ * attacks.  It's not very fast either.  However, it's still used in
+ * standards, and having it available can be useful.
+ */
+
+#ifndef CATACOMB_MD2_H
+#define CATACOMB_MD2_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <mLib/bits.h>
+
+#ifndef CATACOMB_GHASH_H
+#  include "ghash.h"
+#endif
+
+/*----- Magic numbers -----------------------------------------------------*/
+
+#define MD2_BUFSZ 16
+#define MD2_HASHSZ 16
+#define MD2_STATESZ 32
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct md2_ctx {
+  octet c[MD2_BUFSZ];                  /* Checksum buffer */
+  octet h[MD2_BUFSZ];                  /* Hash result buffer */
+  octet buf[MD2_BUFSZ];                        /* Input buffer */
+  unsigned off;                                /* Offset into buffer */
+} md2_ctx;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @md2_compress@ --- *
+ *
+ * Arguments:  @md2_ctx *ctx@ = pointer to context block
+ *             @const void *sbuf@ = pointer to buffer of appropriate size
+ *
+ * Returns:    ---
+ *
+ * Use:                MD2 compression function.
+ */
+
+extern void md2_compress(md2_ctx */*ctx*/, const void */*sbuf*/);
+
+/* --- @md2_init@ --- *
+ *
+ * Arguments:  @md2_ctx *ctx@ = pointer to context block to initialize
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes a context block ready for hashing.
+ */
+
+extern void md2_init(md2_ctx */*ctx*/);
+
+/* --- @md2_set@ --- *
+ *
+ * Arguments:  @md2_ctx *ctx@ = pointer to context block
+ *             @const void *buf@ = pointer to state buffer
+ *             @unsigned long count@ = current count of bytes processed
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes a context block from a given state.  This is
+ *             useful in cases where the initial hash state is meant to be
+ *             secret, e.g., for NMAC and HMAC support.
+ */
+
+extern void md2_set(md2_ctx */*ctx*/, const void */*buf*/,
+                   unsigned long /*count*/);
+
+/* --- @md2_hash@ --- *
+ *
+ * Arguments:  @md2_ctx *ctx@ = pointer to context block
+ *             @const void *buf@ = buffer of data to hash
+ *             @size_t sz@ = size of buffer to hash
+ *
+ * Returns:    ---
+ *
+ * Use:                Hashes a buffer of data.  The buffer may be of any size and
+ *             alignment.
+ */
+
+extern void md2_hash(md2_ctx */*ctx*/, const void */*buf*/, size_t /*sz*/);
+
+/* --- @md2_done@ --- *
+ *
+ * Arguments:  @md2_ctx *ctx@ = pointer to context block
+ *             @void *hash@ = pointer to output buffer
+ *
+ * Returns:    ---
+ *
+ * Use:                Returns the hash of the data read so far.
+ */
+
+extern void md2_done(md2_ctx */*ctx*/, void */*hash*/);
+
+/* --- @md2_state@ --- *
+ *
+ * Arguments:  @md2_ctx *ctx@ = pointer to context
+ *             @void *state@ = pointer to buffer for current state
+ *
+ * Returns:    Number of bytes written to the hash function so far.
+ *
+ * Use:                Returns the current state of the hash function such that
+ *             it can be passed to @md2_set@.
+ */
+
+extern unsigned long md2_state(md2_ctx */*ctx*/, void */*state*/);
+
+/*----- Generic hash interface --------------------------------------------*/
+
+extern const gchash md2;
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif