+++ /dev/null
-/**
- * \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 2006 Develer S.r.l. (http://www.develer.com/)
- *
- * -->
- *
- * \brief TEA Tiny Encription Algorith functions (implementation).
- *
- * \version $Id$
- * \author Francesco Sacchi <batt@develer.com>
- *
- * The Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham
- * of the Cambridge Computer Laboratory
- *
- * Placed in the Public Domain by David Wheeler and Roger Needham.
- *
- * **** ANSI C VERSION ****
- *
- * Notes:
- *
- * TEA is a Feistel cipher with XOR and and addition as the non-linear
- * mixing functions.
- *
- * Takes 64 bits of data in v[0] and v[1]. Returns 64 bits of data in w[0]
- * and w[1]. Takes 128 bits of key in k[0] - k[3].
- *
- * TEA can be operated in any of the modes of DES. Cipher Block Chaining is,
- * for example, simple to implement.
- *
- * n is the number of iterations. 32 is ample, 16 is sufficient, as few
- * as eight may be OK. The algorithm achieves good dispersion after six
- * iterations. The iteration count can be made variable if required.
- *
- * Note this is optimised for 32-bit CPUs with fast shift capabilities. It
- * can very easily be ported to assembly language on most CPUs.
- *
- * delta is chosen to be the real part of (the golden ratio Sqrt(5/4) -
- * 1/2 ~ 0.618034 multiplied by 2^32).
- */
-
-/*#*
- *#* $Log$
- *#* Revision 1.2 2007/09/19 16:23:27 batt
- *#* Fix doxygen warnings.
- *#*
- *#* Revision 1.1 2007/06/07 09:13:40 batt
- *#* Add TEA enc/decryption algorithm.
- *#*
- *#* Revision 1.1 2007/01/10 17:30:10 batt
- *#* Add cryptographic routines.
- *#*
- *#*/
-
-#include "tea.h"
-#include <mware/byteorder.h>
-
-static uint32_t tea_func(uint32_t *in, uint32_t *sum, uint32_t *k)
-{
- return ((*in << 4) + cpu_to_le32(k[0])) ^ (*in + *sum) ^ ((*in >> 5) + cpu_to_le32(k[1]));
-}
-
-/**
- * \brief TEA encryption function.
- * This function encrypts <EM>v</EM> with <EM>k</EM> and returns the
- * encrypted data in <EM>v</EM>.
- * \param _v Array of two long values containing the data block.
- * \param _k Array of four long values containing the key.
- */
-void tea_enc(void *_v, void *_k)
-{
- uint32_t y, z;
- uint32_t sum = 0;
- uint8_t n = ROUNDS;
- uint32_t *v = (uint32_t *)_v;
- uint32_t *k = (uint32_t *)_k;
-
- y=cpu_to_le32(v[0]);
- z=cpu_to_le32(v[1]);
-
- while(n-- > 0)
- {
- sum += DELTA;
- y += tea_func(&z, &sum, &(k[0]));
- z += tea_func(&y, &sum, &(k[2]));
- }
-
- v[0] = le32_to_cpu(y);
- v[1] = le32_to_cpu(z);
-}
-
-/**
- * \brief TEA decryption function.
- * This function decrypts <EM>v</EM> with <EM>k</EM> and returns the
- * decrypted data in <EM>v</EM>.
- * \param _v Array of two long values containing the data block.
- * \param _k Array of four long values containing the key.
- */
-void tea_dec(void *_v, void *_k)
-{
- uint32_t y, z;
- uint32_t sum = DELTA * ROUNDS;
- uint8_t n = ROUNDS;
- uint32_t *v = (uint32_t *)_v;
- uint32_t *k = (uint32_t *)_k;
-
- y = cpu_to_le32(v[0]);
- z = cpu_to_le32(v[1]);
-
- while(n-- > 0)
- {
- z -= tea_func(&y, &sum, &(k[2]));
- y -= tea_func(&z, &sum, &(k[0]));
- sum -= DELTA;
- }
-
- v[0] = le32_to_cpu(y);
- v[1] = le32_to_cpu(z);
-}
-
projects / bertos.git / blobdiff