Add hmac-sha1 module.

[gnulib.git] / lib / hmac-sha1.c

diff --git a/lib/hmac-sha1.c b/lib/hmac-sha1.c
new file mode 100644 (file)
index 0000000..bee7231
--- /dev/null
+++ b/lib/hmac-sha1.c
@@ -0,0 +1,76 @@
+/* hmac-sha1.c -- hashed message authentication codes
+   Copyright (C) 2005 Free Software Foundation, Inc.
+
+   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, 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 Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Written by Simon Josefsson.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "hmac.h"
+
+#include "sha1.h"
+
+#include <string.h>
+
+#define IPAD 0x36
+#define OPAD 0x5c
+
+int
+hmac_sha1 (const void *key, size_t keylen,
+          const void *in, size_t inlen, void *resbuf)
+{
+  struct sha1_ctx inner;
+  struct sha1_ctx outer;
+  char optkeybuf[20];
+  char block[64];
+  char innerhash[20];
+
+  if (keylen > 64)
+    {
+      struct sha1_ctx keyhash;
+
+      sha1_init_ctx (&keyhash);
+      sha1_process_bytes (key, keylen, &keyhash);
+      sha1_finish_ctx (&keyhash, optkeybuf);
+
+      key = optkeybuf;
+      keylen = 20;
+    }
+
+  sha1_init_ctx (&inner);
+
+  memset (block, IPAD, sizeof (block));
+  memxor (block, key, keylen);
+
+  sha1_process_block (block, 64, &inner);
+  sha1_process_bytes (in, inlen, &inner);
+
+  sha1_finish_ctx (&inner, innerhash);
+
+  sha1_init_ctx (&outer);
+
+  memset (block, OPAD, sizeof (block));
+  memxor (block, key, keylen);
+
+  sha1_process_block (block, 64, &outer);
+  sha1_process_bytes (innerhash, 20, &outer);
+
+  sha1_finish_ctx (&outer, resbuf);
+
+  return 0;
+}