321 lines
9.7 KiB
C
321 lines
9.7 KiB
C
/**
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* @file rc2.c
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* @version $Format:%h%d$
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*
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* rc2 cipher implementation.
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*/
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/*
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* Copyright (c) 2013-2016 INSIDE Secure Corporation
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* Copyright (c) PeerSec Networks, 2002-2011
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* All Rights Reserved
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*
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* The latest version of this code is available at http://www.matrixssl.org
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*
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* This software is open source; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This General Public License does NOT permit incorporating this software
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* into proprietary programs. If you are unable to comply with the GPL, a
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* commercial license for this software may be purchased from INSIDE at
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* http://www.insidesecure.com/
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*
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* This program is distributed in WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* http://www.gnu.org/copyleft/gpl.html
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*/
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/******************************************************************************/
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#include "../cryptoApi.h"
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#ifdef USE_MATRIX_RC2
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/******************************************************************************/
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static int32_t psRc2InitKey(const unsigned char *key, uint8_t keylen,
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uint8_t rds, psRc2Key_t *skey);
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static void psRc2EncryptBlock(const unsigned char *pt, unsigned char *ct,
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psRc2Key_t *skey);
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static void psRc2DecryptBlock(const unsigned char *ct, unsigned char *pt,
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psRc2Key_t *skey);
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/* 256-entry permutation table, probably derived somehow from pi */
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static const unsigned char permute[256] = {
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217,120,249,196, 25,221,181,237, 40,233,253,121, 74,160,216,157,
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198,126, 55,131, 43,118, 83,142, 98, 76,100,136, 68,139,251,162,
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23,154, 89,245,135,179, 79, 19, 97, 69,109,141, 9,129,125, 50,
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189,143, 64,235,134,183,123, 11,240,149, 33, 34, 92,107, 78,130,
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84,214,101,147,206, 96,178, 28,115, 86,192, 20,167,140,241,220,
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18,117,202, 31, 59,190,228,209, 66, 61,212, 48,163, 60,182, 38,
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111,191, 14,218, 70,105, 7, 87, 39,242, 29,155,188,148, 67, 3,
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248, 17,199,246,144,239, 62,231, 6,195,213, 47,200,102, 30,215,
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8,232,234,222,128, 82,238,247,132,170,114,172, 53, 77,106, 42,
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150, 26,210,113, 90, 21, 73,116, 75,159,208, 94, 4, 24,164,236,
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194,224, 65,110, 15, 81,203,204, 36,145,175, 80,161,244,112, 57,
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153,124, 58,133, 35,184,180,122,252, 2, 54, 91, 37, 85,151, 49,
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45, 93,250,152,227,138,146,174, 5,223, 41, 16,103,108,186,201,
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211, 0,230,207,225,158,168, 44, 99, 22, 1, 63, 88,226,137,169,
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13, 56, 52, 27,171, 51,255,176,187, 72, 12, 95,185,177,205, 46,
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197,243,219, 71,229,165,156,119, 10,166, 32,104,254,127,193,173
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};
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/******************************************************************************/
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int32_t psRc2Init(psRc2Cbc_t *ctx, const unsigned char *IV,
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const unsigned char *key, uint8_t keylen)
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{
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int32 x, err;
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if (IV == NULL || key == NULL || ctx == NULL) {
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psTraceCrypto("psRc2Init arg fail\n");
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return PS_ARG_FAIL;
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}
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/* setup cipher */
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if ((err = psRc2InitKey(key, keylen, 0, &ctx->key)) != PS_SUCCESS) {
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return err;
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}
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/* copy IV */
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for (x = 0; x < RC2_BLOCKLEN; x++) {
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ctx->IV[x] = IV[x];
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}
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return PS_SUCCESS;
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}
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/******************************************************************************/
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int32_t psRc2Encrypt(psRc2Cbc_t *ctx, const unsigned char *pt,
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unsigned char *ct, uint32_t len)
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{
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int32 x;
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uint32 i;
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unsigned char tmp[RC2_BLOCKLEN];
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if (pt == NULL || ct == NULL || ctx == NULL || (len & 0x7) != 0) {
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psTraceCrypto("Bad parameters to psRc2Encrypt\n");
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return PS_ARG_FAIL;
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}
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for (i = 0; i < len; i += RC2_BLOCKLEN) {
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/* xor IV against plaintext */
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for (x = 0; x < RC2_BLOCKLEN; x++) {
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tmp[x] = pt[x] ^ ctx->IV[x];
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}
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/* encrypt */
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psRc2EncryptBlock(tmp, ct, &ctx->key);
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/* store IV [ciphertext] for a future block */
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for (x = 0; x < RC2_BLOCKLEN; x++) {
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ctx->IV[x] = ct[x];
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}
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ct += RC2_BLOCKLEN;
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pt += RC2_BLOCKLEN;
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}
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memset(tmp, 0x0, sizeof(tmp));
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return len;
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}
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/******************************************************************************/
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int32_t psRc2Decrypt(psRc2Cbc_t *ctx, const unsigned char *ct,
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unsigned char *pt, uint32_t len)
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{
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int32 x;
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uint32 i;
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unsigned char tmp[RC2_BLOCKLEN], tmp2[RC2_BLOCKLEN];
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if (pt == NULL || ct == NULL || ctx == NULL || (len & 0x7) != 0) {
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psTraceCrypto("Bad parameters to psRc2Decrypt\n");
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return PS_ARG_FAIL;
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}
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for (i = 0; i < len; i += RC2_BLOCKLEN) {
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/* decrypt the block from ct into tmp */
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psRc2DecryptBlock(ct, tmp, &ctx->key);
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/* xor IV against the plaintext of the previous step */
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for (x = 0; x < RC2_BLOCKLEN; x++) {
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/* copy CT in case ct == pt */
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tmp2[x] = ct[x];
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/* actually decrypt the byte */
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pt[x] = tmp[x] ^ ctx->IV[x];
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}
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/* replace IV with this current ciphertext */
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for (x = 0; x < RC2_BLOCKLEN; x++) {
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ctx->IV[x] = tmp2[x];
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}
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ct += RC2_BLOCKLEN;
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pt += RC2_BLOCKLEN;
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}
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memset(tmp, 0x0, sizeof(tmp));
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memset(tmp2, 0x0, sizeof(tmp2));
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return len;
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}
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/******************************************************************************/
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/**
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Initialize the LTC_RC2 block cipher
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@param key The symmetric key you wish to pass
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@param keylen The key length in bytes
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@param num_rounds The number of rounds desired (0 for default)
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@param skey The key in as scheduled by this function.
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@return CRYPT_OK if successful
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*/
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static int32_t psRc2InitKey(const unsigned char *key, uint8_t keylen,
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uint8_t num_rounds, psRc2Key_t *ctx)
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{
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unsigned char tmp[128];
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uint32_t *xkey;
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uint32_t T8, TM;
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int32_t i, bits;
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//if (keylen < 8 || keylen > 128) {
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// return PS_ARG_FAIL;
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//}
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if (num_rounds != 0 && num_rounds != 16) {
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return PS_ARG_FAIL;
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}
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xkey = ctx->xkey;
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for (i = 0; i < (int32)keylen; i++) {
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tmp[i] = key[i] & 255;
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}
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/* Phase 1: Expand input key to 128 bytes */
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if (keylen < 128) {
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for (i = keylen; i < 128; i++) {
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tmp[i] = permute[(tmp[i - 1] + tmp[i - keylen]) & 255];
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}
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}
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/* Phase 2 - reduce effective key size to "bits" */
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bits = keylen<<3;
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T8 = (uint32_t)(bits+7)>>3;
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TM = (255 >> (uint32_t)(7 & -bits));
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tmp[128 - T8] = permute[tmp[128 - T8] & TM];
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for (i = 127 - T8; i >= 0; i--) {
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tmp[i] = permute[tmp[i + 1] ^ tmp[i + T8]];
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}
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/* Phase 3 - copy to xkey in little-endian order */
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for (i = 0; i < 64; i++) {
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xkey[i] = (uint32_t)tmp[2*i] + ((uint32_t)tmp[2*i+1] << 8);
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}
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return PS_SUCCESS;
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}
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/******************************************************************************/
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/**
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Encrypts a block of text with LTC_RC2
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@param pt The input plaintext (8 bytes)
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@param ct The output ciphertext (8 bytes)
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@param skey The key as scheduled
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@return CRYPT_OK if successful
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*/
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static void psRc2EncryptBlock(const unsigned char *pt, unsigned char *ct,
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psRc2Key_t *ctx)
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{
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uint32_t *xkey;
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uint32_t x76, x54, x32, x10, i;
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xkey = ctx->xkey;
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x76 = ((uint32_t)pt[7] << 8) + (uint32_t)pt[6];
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x54 = ((uint32_t)pt[5] << 8) + (uint32_t)pt[4];
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x32 = ((uint32_t)pt[3] << 8) + (uint32_t)pt[2];
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x10 = ((uint32_t)pt[1] << 8) + (uint32_t)pt[0];
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for (i = 0; i < 16; i++) {
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x10 = (x10 + (x32 & ~x76) + (x54 & x76) + xkey[4*i+0]) & 0xFFFF;
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x10 = ((x10 << 1) | (x10 >> 15));
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x32 = (x32 + (x54 & ~x10) + (x76 & x10) + xkey[4*i+1]) & 0xFFFF;
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x32 = ((x32 << 2) | (x32 >> 14));
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x54 = (x54 + (x76 & ~x32) + (x10 & x32) + xkey[4*i+2]) & 0xFFFF;
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x54 = ((x54 << 3) | (x54 >> 13));
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x76 = (x76 + (x10 & ~x54) + (x32 & x54) + xkey[4*i+3]) & 0xFFFF;
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x76 = ((x76 << 5) | (x76 >> 11));
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if (i == 4 || i == 10) {
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x10 = (x10 + xkey[x76 & 63]) & 0xFFFF;
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x32 = (x32 + xkey[x10 & 63]) & 0xFFFF;
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x54 = (x54 + xkey[x32 & 63]) & 0xFFFF;
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x76 = (x76 + xkey[x54 & 63]) & 0xFFFF;
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}
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}
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ct[0] = (unsigned char)x10;
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ct[1] = (unsigned char)(x10 >> 8);
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ct[2] = (unsigned char)x32;
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ct[3] = (unsigned char)(x32 >> 8);
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ct[4] = (unsigned char)x54;
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ct[5] = (unsigned char)(x54 >> 8);
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ct[6] = (unsigned char)x76;
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ct[7] = (unsigned char)(x76 >> 8);
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}
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/******************************************************************************/
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/**
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Decrypts a block of text with LTC_RC2
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@param ct The input ciphertext (8 bytes)
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@param pt The output plaintext (8 bytes)
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@param skey The key as scheduled
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@return CRYPT_OK if successful
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*/
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static void psRc2DecryptBlock(const unsigned char *ct, unsigned char *pt,
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psRc2Key_t *ctx)
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{
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uint32_t x76, x54, x32, x10;
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uint32_t *xkey;
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int i;
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xkey = ctx->xkey;
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x76 = ((uint32_t)ct[7] << 8) + (uint32_t)ct[6];
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x54 = ((uint32_t)ct[5] << 8) + (uint32_t)ct[4];
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x32 = ((uint32_t)ct[3] << 8) + (uint32_t)ct[2];
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x10 = ((uint32_t)ct[1] << 8) + (uint32_t)ct[0];
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for (i = 15; i >= 0; i--) {
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if (i == 4 || i == 10) {
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x76 = (x76 - xkey[x54 & 63]) & 0xFFFF;
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x54 = (x54 - xkey[x32 & 63]) & 0xFFFF;
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x32 = (x32 - xkey[x10 & 63]) & 0xFFFF;
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x10 = (x10 - xkey[x76 & 63]) & 0xFFFF;
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}
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x76 = ((x76 << 11) | (x76 >> 5));
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x76 = (x76 - ((x10 & ~x54) + (x32 & x54) + xkey[4*i+3])) & 0xFFFF;
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x54 = ((x54 << 13) | (x54 >> 3));
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x54 = (x54 - ((x76 & ~x32) + (x10 & x32) + xkey[4*i+2])) & 0xFFFF;
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x32 = ((x32 << 14) | (x32 >> 2));
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x32 = (x32 - ((x54 & ~x10) + (x76 & x10) + xkey[4*i+1])) & 0xFFFF;
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x10 = ((x10 << 15) | (x10 >> 1));
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x10 = (x10 - ((x32 & ~x76) + (x54 & x76) + xkey[4*i+0])) & 0xFFFF;
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}
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pt[0] = (unsigned char)x10;
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pt[1] = (unsigned char)(x10 >> 8);
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pt[2] = (unsigned char)x32;
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pt[3] = (unsigned char)(x32 >> 8);
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pt[4] = (unsigned char)x54;
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pt[5] = (unsigned char)(x54 >> 8);
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pt[6] = (unsigned char)x76;
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pt[7] = (unsigned char)(x76 >> 8);
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}
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#endif /* USE_RC2 */
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/******************************************************************************/
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