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[u/mdw/catacomb] / symm / md5.h

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+/* -*-c-*-
+ *
+ * The MD5 message digest function
+ *
+ * (c) 1998 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 MD5 hash function ------------------------------------*
+ *
+ * MD5 was designed by Ron Rivest.  It was intended to be a more conservative
+ * design than the slightly earlier MD4, and indeed while MD4 has been pretty
+ * much demolished by subsequent cryptanalysis, MD5 is still standing
+ * shakily.  It's provided here not because the author recommends its use but
+ * because it's a common standard, and is often handy in non-cryptographic
+ * applications.  It's also still useful in constructions such as HMAC.
+ */
+
+#ifndef CATACOMB_MD5_H
+#define CATACOMB_MD5_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <mLib/bits.h>
+
+#ifndef CATACOMB_GHASH_H
+#  include "ghash.h"
+#endif
+
+/*----- Magic numbers -----------------------------------------------------*/
+
+#define MD5_BUFSZ 64
+#define MD5_HASHSZ 16
+#define MD5_STATESZ 16
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct md5_ctx {
+  uint32 a, b, c, d;                   /* Chaining variables */
+  uint32 nl, nh;                       /* Byte count so far */
+  unsigned off;                                /* Offset into buffer */
+  octet buf[MD5_BUFSZ];                        /* Accumulation buffer */
+} md5_ctx;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @md5_compress@ --- *
+ *
+ * Arguments:  @md5_ctx *ctx@ = pointer to context block
+ *             @const void *sbuf@ = pointer to buffer of appropriate size
+ *
+ * Returns:    ---
+ *
+ * Use:                MD5 compression function.
+ */
+
+extern void md5_compress(md5_ctx */*ctx*/, const void */*sbuf*/);
+
+/* --- @md5_init@ --- *
+ *
+ * Arguments:  @md5_ctx *ctx@ = pointer to context block to initialize
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes a context block ready for hashing.
+ */
+
+extern void md5_init(md5_ctx */*ctx*/);
+
+/* --- @md5_set@ --- *
+ *
+ * Arguments:  @md5_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 md5_set(md5_ctx */*ctx*/, const void */*buf*/,
+                   unsigned long /*count*/);
+
+/* --- @md5_hash@ --- *
+ *
+ * Arguments:  @md5_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 md5_hash(md5_ctx */*ctx*/, const void */*buf*/, size_t /*sz*/);
+
+/* --- @md5_done@ --- *
+ *
+ * Arguments:  @md5_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 md5_done(md5_ctx */*ctx*/, void */*hash*/);
+
+/* --- @md5_state@ --- *
+ *
+ * Arguments:  @md5_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 @md5_set@.
+ */
+
+extern unsigned long md5_state(md5_ctx */*ctx*/, void */*state*/);
+
+/*----- Generic hash interface --------------------------------------------*/
+
+extern const gchash md5;
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif