gcrypt hasher implementation

2009-06-09 11:18:56 +02:00
parent 513a1a2835
commit f908ff9f91
4 changed files with 220 additions and 1 deletions
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2009 Martin Willi
+ * Hochschule fuer Technik Rapperswil 
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program 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 General Public License
+ * for more details.
+ */
+
+#include "gcrypt_hasher.h"
+
+#include <debug.h>
+
+#include <gcrypt.h>
+
+typedef struct private_gcrypt_hasher_t private_gcrypt_hasher_t;
+
+/**
+ * Private data of gcrypt_hasher_t
+ */
+struct private_gcrypt_hasher_t {
+	
+	/**
+	 * Public part of this class.
+	 */
+	gcrypt_hasher_t public;
+	
+	/**
+	 * gcrypt hasher context
+	 */
+	gcry_md_hd_t hd;
+};
+
+/**
+ * Implementation of hasher_t.get_hash_size.
+ */
+static size_t get_hash_size(private_gcrypt_hasher_t *this)
+{
+	return gcry_md_get_algo_dlen(gcry_md_get_algo(this->hd));
+}
+
+/**
+ * Implementation of hasher_t.reset.
+ */
+static void reset(private_gcrypt_hasher_t *this)
+{
+	gcry_md_reset(this->hd);
+}
+
+/**
+ * Implementation of hasher_t.get_hash.
+ */
+static void get_hash(private_gcrypt_hasher_t *this, chunk_t chunk,
+					 u_int8_t *hash)
+{
+	gcry_md_write(this->hd, chunk.ptr, chunk.len);
+	if (hash)
+	{
+		memcpy(hash, gcry_md_read(this->hd, 0), get_hash_size(this));
+		gcry_md_reset(this->hd);
+	}
+}
+
+/**
+ * Implementation of hasher_t.allocate_hash.
+ */
+static void allocate_hash(private_gcrypt_hasher_t *this, chunk_t chunk,
+						  chunk_t *hash)
+{
+	if (hash)
+	{
+		*hash = chunk_alloc(get_hash_size(this));
+		get_hash(this, chunk, hash->ptr);
+	}
+	else
+	{
+		get_hash(this, chunk, NULL);
+	}
+}
+
+/**
+ * Implementation of hasher_t.destroy.
+ */
+static void destroy (private_gcrypt_hasher_t *this)
+{
+	gcry_md_close(this->hd);
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+gcrypt_hasher_t *gcrypt_hasher_create(hash_algorithm_t algo)
+{
+	private_gcrypt_hasher_t *this;
+	int gcrypt_alg;
+	gcry_error_t err;
+	
+	switch (algo)
+	{
+		case HASH_MD2:
+			gcrypt_alg = GCRY_MD_MD2;
+			break;
+		case HASH_MD4:
+			gcrypt_alg = GCRY_MD_MD4;
+			break;
+		case HASH_MD5:
+			gcrypt_alg = GCRY_MD_MD5;
+			break;
+		case HASH_SHA1:
+			gcrypt_alg = GCRY_MD_SHA1;
+			break;
+		case HASH_SHA256:
+			gcrypt_alg = GCRY_MD_SHA256;
+			break;
+		case HASH_SHA384:
+			gcrypt_alg = GCRY_MD_SHA384;
+			break;
+		case HASH_SHA512:
+			gcrypt_alg = GCRY_MD_SHA512;
+			break;
+		default:
+			return NULL;
+	}
+	
+	this = malloc_thing(private_gcrypt_hasher_t);
+	
+	err = gcry_md_open(&this->hd, gcrypt_alg, 0);
+	if (err)
+	{
+		DBG1("grcy_md_open(%N) failed: %s",
+			 hash_algorithm_names, algo, gpg_strerror(err));
+		free(this);
+		return NULL;
+	}
+	
+	this->public.hasher_interface.get_hash = (void (*) (hasher_t*, chunk_t, u_int8_t*))get_hash;
+	this->public.hasher_interface.allocate_hash = (void (*) (hasher_t*, chunk_t, chunk_t*))allocate_hash;
+	this->public.hasher_interface.get_hash_size = (size_t (*) (hasher_t*))get_hash_size;
+	this->public.hasher_interface.reset = (void (*) (hasher_t*))reset;
+	this->public.hasher_interface.destroy = (void (*) (hasher_t*))destroy;
+	
+	return &this->public;
+}
+