From a60a822ef23e4e9e3d312a41ae35ef38de9a9d46 Mon Sep 17 00:00:00 2001 From: Gregory Nutt Date: Tue, 19 Jan 2016 16:46:25 -0600 Subject: [PATCH] Separate TEA encryption and decryption to separate files --- libc/misc/Make.defs | 3 +- libc/misc/{lib_tea.c => lib_tea_decrypt.c} | 35 +-------- libc/misc/lib_tea_encrypt.c | 88 ++++++++++++++++++++++ 3 files changed, 92 insertions(+), 34 deletions(-) rename libc/misc/{lib_tea.c => lib_tea_decrypt.c} (81%) create mode 100644 libc/misc/lib_tea_encrypt.c diff --git a/libc/misc/Make.defs b/libc/misc/Make.defs index 7b53111e8d..6c0a37ac7c 100644 --- a/libc/misc/Make.defs +++ b/libc/misc/Make.defs @@ -35,7 +35,8 @@ # Add the internal C files to the build -CSRCS += lib_stream.c lib_filesem.c lib_utsname.c lib_tea.c +CSRCS += lib_stream.c lib_filesem.c lib_utsname.c +CSRCS += lib_tea_encrypt.c lib_tea_decrypt.c # Add C files that depend on file OR socket descriptors diff --git a/libc/misc/lib_tea.c b/libc/misc/lib_tea_decrypt.c similarity index 81% rename from libc/misc/lib_tea.c rename to libc/misc/lib_tea_decrypt.c index 927357ff40..378407879e 100644 --- a/libc/misc/lib_tea.c +++ b/libc/misc/lib_tea_decrypt.c @@ -1,6 +1,6 @@ /**************************************************************************** - * libc/misc/lib_tea.c - * Tiny Encryption Algorithm + * libc/misc/lib_tea_decrypt.c + * Tiny Encryption Algorithm - Decryption support * * Copyright (C) 2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt @@ -56,37 +56,6 @@ * Public Functions ****************************************************************************/ -/**************************************************************************** - * Name: tea_encrypt - * - * Input Parameters: - * value = 2 x 32-bit value (input/output) - * key = 4 x 32-bit Cache key (input) - * - ****************************************************************************/ - -void tea_encrypt(FAR uint32_t *value, FAR const uint32_t *key) -{ - uint32_t v0 = value[0]; - uint32_t v1 = value[1]; - uint32_t sum = 0; - int i; - - /* Basic cycle start */ - - for (i = 0; i < 32; i++) - { - sum += TEA_KEY_SCHEDULE_CONSTANT; - v0 += ((v1 << 4) + key[0]) ^ (v1 + sum) ^ ((v1 >> 5) + key[1]); - v1 += ((v0 << 4) + key[2]) ^ (v0 + sum) ^ ((v0 >> 5) + key[3]); - } - - /* End cycle */ - - value[0] = v0; - value[1] = v1; -} - /**************************************************************************** * Name: tea_decrypt * diff --git a/libc/misc/lib_tea_encrypt.c b/libc/misc/lib_tea_encrypt.c new file mode 100644 index 0000000000..7ea5e545f7 --- /dev/null +++ b/libc/misc/lib_tea_encrypt.c @@ -0,0 +1,88 @@ +/**************************************************************************** + * libc/misc/lib_tea_encrypt.c + * Tiny Encryption Algorithm - Encryption support + * + * Copyright (C) 2016 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt + * + * https://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm: "Following is + * an adaptation of the reference encryption and decryption routines in C, + * released into the public domain by David Wheeler and Roger Needham." + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include +#include + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +#define TEA_KEY_SCHEDULE_CONSTANT 0x9e3779b9 +#define TEA_SUM_SETUP_CONSTANT 0xc6ef3720 + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: tea_encrypt + * + * Input Parameters: + * value = 2 x 32-bit value (input/output) + * key = 4 x 32-bit Cache key (input) + * + ****************************************************************************/ + +void tea_encrypt(FAR uint32_t *value, FAR const uint32_t *key) +{ + uint32_t v0 = value[0]; + uint32_t v1 = value[1]; + uint32_t sum = 0; + int i; + + /* Basic cycle start */ + + for (i = 0; i < 32; i++) + { + sum += TEA_KEY_SCHEDULE_CONSTANT; + v0 += ((v1 << 4) + key[0]) ^ (v1 + sum) ^ ((v1 >> 5) + key[1]); + v1 += ((v0 << 4) + key[2]) ^ (v0 + sum) ^ ((v0 >> 5) + key[3]); + } + + /* End cycle */ + + value[0] = v0; + value[1] = v1; +}