New files.

Rev: src/nettle/hmac-md5.c:1.1
Rev: src/nettle/hmac.c:1.1
Rev: src/nettle/hmac.h:1.1
Rev: src/nettle/md5-meta.c:1.1
Rev: src/nettle/nettle-meta.h:1.1
Rev: src/nettle/sha1-meta.c:1.1
Rev: src/nettle/sha256-meta.c:1.1

1 files changed, 90 insertions, 0 deletions

diff --git a/hmac.c b/hmac.c
new file mode 100644
index 00000000..4ea273cd
--- /dev/null
+++ b/hmac.c
@@ -0,0 +1,90 @@
+/* hmac.c
+ *
+ * HMAC message authentication code.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2001 Niels Möller
+ *  
+ * The nettle library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ * 
+ * The nettle library 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 Lesser General Public
+ * License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the nettle library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#include "hmac.h"
+
+#include "memxor.h"
+
+#include <assert.h>
+
+#define IPAD 0x36
+#define OPAD 0x5c
+
+void
+hmac_init(void *outer, void *inner, void *state,
+	  struct hmac_info *info,
+	  unsigned key_length, const uint8_t *key)
+{
+  uint8_t pad = alloca(info->block_size);
+  
+  info->init(outer);
+  info->init(inner);
+
+  if (length > info->block_size)
+    {
+      /* Reduce key to the algorithm's hash size. Use the area pointed
+       * to by state for the temporary state. */
+
+      uint8_t *digest = alloca(info->digest_size);
+
+      info->init(state);
+      info->update(state, key_length, key);
+      info->digest(state, info->digest_size, digest);
+
+      key = digest;
+      key_length = info->digest_size;
+    }
+
+  assert(key_size <= info->block_size);
+  
+  memset(pad, OPAD, info->block_size);
+  memxor(pad, key, key_length);
+
+  info->update(outer, info->block_size, pad);
+
+  memset(pad, IPAD, info->block_size);
+  memxor(pad, key, key_length);
+
+  info->update(inner, info->block_size, pad);
+
+  memcpy(state, inner, info->ctx_size);
+}
+
+void
+hmac_digest(void *outer, void *inner, void *state
+	    struct hmac_info *info, 	    
+	    unsigned length, uint8_t *dst)
+{
+  uint8_t *digest = alloca(info->digest_size);
+
+  info->digest(state, info->digest_size, digest);
+
+  memcpy(outer, state, info->ctx_size);
+
+  info->update(state, info->digest_size, digest);
+  info->digest(state, length, dst);
+
+  memcpy(state, inner, info->ctx_size);
+}