SEC: add HMAC implementation.

[bertos.git] / bertos / sec / mac / hmac.c

diff --git a/bertos/sec/mac/hmac.c b/bertos/sec/mac/hmac.c
new file mode 100644 (file)
index 0000000..1616ec4
--- /dev/null
+++ b/bertos/sec/mac/hmac.c
@@ -0,0 +1,105 @@
+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2010 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \brief HMAC implementation
+ * \author Giovanni Bajo <rasky@develer.com>
+ * 
+ */
+
+#include "hmac.h"
+#include <sec/util.h>
+#include <string.h>
+
+
+static void HMAC_set_key(Mac *m, const uint8_t *key, size_t key_len)
+{
+       HMAC_Context *ctx = (HMAC_Context *)m;
+
+       memset(ctx->key, 0, ctx->m.key_len);
+       if (key_len <= ctx->m.key_len)
+               memcpy(ctx->key, key, key_len);         
+       else
+       {
+               hash_begin(ctx->h);
+               hash_update(ctx->h, key, key_len);
+               memcpy(ctx->key, hash_final(ctx->h), hash_digest_len(ctx->h));
+       }
+       
+       xor_block_const(ctx->key, ctx->key, 0x5C, ctx->m.key_len);
+}
+
+static void HMAC_begin(Mac *m)
+{
+       HMAC_Context *ctx = (HMAC_Context *)m;
+       int klen = ctx->m.key_len;
+       
+       xor_block_const(ctx->key, ctx->key, 0x36^0x5C, klen);
+       hash_begin(ctx->h);
+       hash_update(ctx->h, ctx->key, klen);
+}
+
+static void HMAC_update(Mac *m, const uint8_t *data, size_t len)
+{
+       HMAC_Context *ctx = (HMAC_Context *)m;
+       hash_update(ctx->h, data, len);
+}
+
+static uint8_t *HMAC_final(Mac *m)
+{
+       HMAC_Context *ctx = (HMAC_Context *)m;
+       int hlen = hash_digest_len(ctx->h);
+
+       uint8_t temp[hlen];
+       memcpy(temp, hash_final(ctx->h), hlen);
+       
+       xor_block_const(ctx->key, ctx->key, 0x5C^0x36, ctx->m.key_len);
+       hash_begin(ctx->h);
+       hash_update(ctx->h, ctx->key, ctx->m.key_len);
+       hash_update(ctx->h, temp, hlen);
+       
+       PURGE(temp);
+       return hash_final(ctx->h);
+}
+
+/*********************************************************************/
+
+void HMAC_init(HMAC_Context *ctx, Hash *h)
+{
+       ctx->h = h;
+       ctx->m.key_len = hash_block_len(h);
+       ctx->m.digest_len = hash_digest_len(h);
+       ctx->m.set_key = HMAC_set_key;
+       ctx->m.begin = HMAC_begin;
+       ctx->m.update = HMAC_update;
+       ctx->m.final = HMAC_final;      
+       ASSERT(sizeof(ctx->key) >= ctx->m.key_len);
+}