SEC: add implementations for PBKDF1 and PBKDF2.

[bertos.git] / bertos / sec / kdf / pbkdf1.c

diff --git a/bertos/sec/kdf/pbkdf1.c b/bertos/sec/kdf/pbkdf1.c
new file mode 100644 (file)
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+++ b/bertos/sec/kdf/pbkdf1.c
@@ -0,0 +1,106 @@
+/**
+ * \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 PBKDF1 implementation
+ * \author Giovanni Bajo <rasky@develer.com>
+ * 
+ */
+
+#include "pbkdf1.h"
+#include <sec/hash.h>
+#include <sec/util.h>
+
+
+static void PBKDF1_begin(Kdf *ctx_, const char *pwd, size_t pwd_len,
+                                            const uint8_t *salt, size_t salt_len)
+{
+       PBKDF1_Context *ctx = (PBKDF1_Context *)ctx_;
+
+       hash_begin(ctx->hash);
+       hash_update(ctx->hash, pwd, pwd_len);
+       hash_update(ctx->hash, salt, salt_len);
+       
+       ctx->kdf.to_read = 0;
+       ctx->kdf.block = NULL;
+}
+
+static void PBKDF1_next(Kdf *ctx_)
+{
+       PBKDF1_Context *ctx = (PBKDF1_Context *)ctx_;
+       
+       // PBKDF1 will generate only one block of data (whose len depends
+       // on the underlying hash function). After that, the generation stops
+       // with an ASSERT. If you use PKBDF1, you are supposed to be aware
+       // of this limit while designing your algorithm.
+       ASSERT(ctx->kdf.block == NULL);
+
+       int hlen = hash_digest_len(ctx->hash);
+       uint8_t temp[hlen];
+       uint8_t *final = hash_final(ctx->hash);
+       
+       for (uint32_t i=0; i<ctx->iterations-1; i++)
+       {
+               memcpy(temp, final, hlen);
+               hash_begin(ctx->hash);
+               hash_update(ctx->hash, temp, hlen);
+               final = hash_final(ctx->hash);
+       }
+
+       PURGE(temp);
+
+       ctx->kdf.to_read = ctx->kdf.block_len;
+       ctx->kdf.block = final;
+}
+
+/**********************************************************************/
+
+// Default iteration count. The RFC does not specify a "good" default
+// value; it just says that this should be a high value to slow down
+// computations. Since slowing down is not much of a concern for an
+// embedded system, we settle for a value which is not too big.
+#define PBKDF1_DEFAULT_ITERATIONS      100
+
+
+void PBKDF1_init(PBKDF1_Context *ctx, Hash *h)
+{
+       ctx->hash = h;
+       ctx->iterations = PBKDF1_DEFAULT_ITERATIONS;
+       ctx->kdf.begin = PBKDF1_begin;
+       ctx->kdf.next = PBKDF1_next;
+       ctx->kdf.block_len = hash_digest_len(h);
+}
+
+void PBKDF1_set_iterations(Kdf *ctx_, uint32_t iterations)
+{
+       PBKDF1_Context *ctx = (PBKDF1_Context *)ctx_;
+       ctx->iterations = iterations;
+}