Support for pbkdf2.

1 files changed, 94 insertions, 0 deletions

diff --git a/pbkdf2.c b/pbkdf2.c
new file mode 100644
index 00000000..e70c3017
--- /dev/null
+++ b/pbkdf2.c
@@ -0,0 +1,94 @@
+/* pbkdf2.c
+ *
+ * PKCS #5 password-based key derivation function PBKDF2, see RFC 2898.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2012 Simon Josefsson
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02111-1301, USA.
+ */
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "pbkdf2.h"
+
+#include "macros.h"
+#include "memxor.h"
+#include "nettle-internal.h"
+
+void
+pbkdf2 (void *mac_ctx, unsigned digest_size,
+	nettle_hash_update_func *update,
+	nettle_hash_digest_func *digest,
+	unsigned length, uint8_t *dst,
+	unsigned iterations,
+	unsigned salt_length, const uint8_t *salt)
+{
+  TMP_DECL(U, uint8_t, NETTLE_MAX_HASH_DIGEST_SIZE);
+  TMP_DECL(T, uint8_t, NETTLE_MAX_HASH_DIGEST_SIZE);
+  
+  unsigned int u;
+  unsigned int l;
+  unsigned int r;
+  unsigned int i;
+  char tmp[4];
+
+  if (iterations == 0)
+    return;
+
+  if (length == 0)
+    return;
+
+  l = ((length - 1) / digest_size) + 1;
+  r = length - (l - 1) * digest_size;
+
+  TMP_ALLOC (U, digest_size);
+  TMP_ALLOC (T, digest_size);
+
+  for (i = 1; i <= l; i++)
+    {
+      memset (T, 0, digest_size);
+
+      for (u = 1; u <= iterations; u++)
+	{
+	  if (u == 1)
+	    {
+	      WRITE_UINT32 (tmp, i);
+
+	      update (mac_ctx, salt_length, salt);
+	      update (mac_ctx, 4, tmp);
+	    }
+	  else
+	    {
+	      update (mac_ctx, digest_size, U);
+	    }
+
+	  digest (mac_ctx, digest_size, U);
+
+	  memxor (T, U, digest_size);
+	}
+
+      memcpy (dst + (i - 1) * digest_size, T, i == l ? r : digest_size);
+    }
+}