SEC: Add symmetric ciphers generic interface.

[bertos.git] / bertos / sec / cipher.c

diff --git a/bertos/sec/cipher.c b/bertos/sec/cipher.c
new file mode 100644 (file)
index 0000000..22bebe6
--- /dev/null
+++ b/bertos/sec/cipher.c
@@ -0,0 +1,82 @@
+/**
+ * \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 Generic interface for symmetric block ciphers.
+ * \author Giovanni Bajo <rasky@develer.com>
+ *
+ */
+
+#include "cipher.h"
+#include <sec/util.h>
+
+void cipher_cbc_encrypt(BlockCipher *c, void *block)
+{
+       xor_block(c->buf, c->buf, block, c->block_len);
+       c->enc_block(c, c->buf);
+       memcpy(block, c->buf, c->block_len);
+}
+
+void cipher_cbc_decrypt(BlockCipher *c, void *block)
+{
+       uint8_t temp[c->block_len];
+       memcpy(temp, block, c->block_len);
+
+       c->dec_block(c, block);
+       xor_block(block, block, c->buf, c->block_len);
+
+       memcpy(c->buf, temp, c->block_len);
+}
+
+static void ctr_increment(void *buf, size_t len)
+{
+       uint8_t *data = (uint8_t*)buf;
+       while (len--)
+               if (LIKELY(++data[len] != 0))
+                       return;
+}
+
+void cipher_ctr_encrypt(BlockCipher *c, void *block)
+{
+       uint8_t temp[c->block_len];
+
+       memcpy(temp, c->buf, c->block_len);
+       c->enc_block(c, temp);
+       xor_block(block, block, temp, c->block_len);
+
+       PURGE(temp);
+       ctr_increment(c->buf, c->block_len);
+}
+
+void cipher_ctr_decrypt(BlockCipher *c, void *block)
+{
+       cipher_ctr_encrypt(c, block);
+}