304 lines
7.8 KiB
C
304 lines
7.8 KiB
C
/* idea.c
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*
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* Copyright (C) 2006-2020 wolfSSL Inc.
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*
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* This file is part of wolfSSL.
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*
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* wolfSSL is free software; 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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* wolfSSL is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <wolfssl/wolfcrypt/settings.h>
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#ifdef HAVE_IDEA
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#include <wolfssl/wolfcrypt/idea.h>
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#include <wolfssl/wolfcrypt/error-crypt.h>
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#include <wolfssl/wolfcrypt/logging.h>
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#ifdef NO_INLINE
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#include <wolfssl/wolfcrypt/misc.h>
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#else
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#define WOLFSSL_MISC_INCLUDED
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#include <wolfcrypt/src/misc.c>
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#endif
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/* multiplication of x and y modulo 2^16+1
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* IDEA specify a special case when an entry value is 0 ( x or y)
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* then it must be replaced by 2^16
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*/
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static WC_INLINE word16 idea_mult(word16 x, word16 y)
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{
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long mul, res;
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mul = (long)x * (long)y;
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if (mul) {
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res = (mul & IDEA_MASK) - ((word32)mul >> 16);
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if (res <= 0)
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res += IDEA_MODULO;
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return (word16) (res & IDEA_MASK);
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}
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if (!x)
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return ((IDEA_MODULO - y) & IDEA_MASK);
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/* !y */
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return ((IDEA_MODULO - x) & IDEA_MASK);
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}
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/* compute 1/a modulo 2^16+1 using Extended euclidean algorithm
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* adapted from fp_invmod */
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static WC_INLINE word16 idea_invmod(word16 x)
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{
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int u, v, b, d;
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if (x <= 1)
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return x;
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u = IDEA_MODULO;
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v = x;
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d = 1;
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b = 0;
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do {
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while (!(u & 1)) {
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u >>= 1;
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if (b & 1)
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b -= IDEA_MODULO;
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b >>= 1;
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}
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while (!(v & 1)) {
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v >>= 1;
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if (d & 1) {
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d -= IDEA_MODULO;
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}
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d >>= 1;
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}
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if (u >= v) {
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u -= v;
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b -= d;
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} else {
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v -= u;
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d -= b;
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}
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} while (u != 0);
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/* d is now the inverse, put positive value if required */
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while (d < 0)
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d += IDEA_MODULO;
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/* d must be < IDEA_MODULO */
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while (d >= (int)IDEA_MODULO)
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d -= IDEA_MODULO;
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return (word16)(d & IDEA_MASK);
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}
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/* generate the 52 16-bits key sub-blocks from the 128 key */
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int wc_IdeaSetKey(Idea *idea, const byte* key, word16 keySz,
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const byte *iv, int dir)
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{
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word16 idx = 0;
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word32 t;
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short i;
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if (idea == NULL || key == NULL || keySz != IDEA_KEY_SIZE ||
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(dir != IDEA_ENCRYPTION && dir != IDEA_DECRYPTION))
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return BAD_FUNC_ARG;
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/* initial key schedule for 0 -> 7 */
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for (i = 0; i < IDEA_ROUNDS; i++) {
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idea->skey[i] = (word16)key[idx++] << 8;
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idea->skey[i] |= (word16)key[idx++];
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}
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/* shift phase key schedule for 8 -> 51 */
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for (i = IDEA_ROUNDS; i < IDEA_SK_NUM; i++) {
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t = (word32)idea->skey[((i+1) & 7) ? i-7 : i-15] << 9;
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t |= (word32)idea->skey[((i+2) & 7) < 2 ? i-14 : i-6] >> 7;
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idea->skey[i] = (word16)(t & IDEA_MASK);
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}
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/* compute decryption key from encryption key */
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if (dir == IDEA_DECRYPTION) {
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word16 enckey[IDEA_SK_NUM];
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/* put encryption key in tmp buffer */
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XMEMCPY(enckey, idea->skey, sizeof(idea->skey));
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idx = 0;
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idea->skey[6*IDEA_ROUNDS] = idea_invmod(enckey[idx++]);
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idea->skey[6*IDEA_ROUNDS+1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
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idea->skey[6*IDEA_ROUNDS+2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
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idea->skey[6*IDEA_ROUNDS+3] = idea_invmod(enckey[idx++]);
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for (i = 6*(IDEA_ROUNDS-1); i >= 0; i -= 6) {
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idea->skey[i+4] = enckey[idx++];
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idea->skey[i+5] = enckey[idx++];
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idea->skey[i] = idea_invmod(enckey[idx++]);
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if (i) {
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idea->skey[i+2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
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idea->skey[i+1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
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}
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else {
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idea->skey[1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
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idea->skey[2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
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}
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idea->skey[i+3] = idea_invmod(enckey[idx++]);
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}
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/* erase temporary buffer */
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ForceZero(enckey, sizeof(enckey));
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}
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/* set the iv */
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return wc_IdeaSetIV(idea, iv);
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}
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/* set the IV in the Idea key structure */
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int wc_IdeaSetIV(Idea *idea, const byte* iv)
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{
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if (idea == NULL)
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return BAD_FUNC_ARG;
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if (iv != NULL)
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XMEMCPY(idea->reg, iv, IDEA_BLOCK_SIZE);
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else
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XMEMSET(idea->reg, 0, IDEA_BLOCK_SIZE);
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return 0;
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}
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/* encryption/decryption for a block (64 bits)
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*/
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int wc_IdeaCipher(Idea *idea, byte* out, const byte* in)
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{
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word32 t1, t2;
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word16 i, skey_idx = 0, idx = 0;
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word16 x[4];
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if (idea == NULL || out == NULL || in == NULL) {
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return BAD_FUNC_ARG;
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}
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/* put input byte block in word16 */
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for (i = 0; i < IDEA_BLOCK_SIZE/2; i++) {
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x[i] = (word16)in[idx++] << 8;
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x[i] |= (word16)in[idx++];
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}
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for (i = 0; i < IDEA_ROUNDS; i++) {
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x[0] = idea_mult(x[0], idea->skey[skey_idx++]);
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x[1] = ((word32)x[1] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
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x[2] = ((word32)x[2] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
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x[3] = idea_mult(x[3], idea->skey[skey_idx++]);
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t2 = x[0] ^ x[2];
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t2 = idea_mult((word16)t2, idea->skey[skey_idx++]);
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t1 = (t2 + (x[1] ^ x[3])) & IDEA_MASK;
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t1 = idea_mult((word16)t1, idea->skey[skey_idx++]);
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t2 = (t1 + t2) & IDEA_MASK;
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x[0] ^= t1;
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x[3] ^= t2;
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t2 ^= x[1];
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x[1] = x[2] ^ (word16)t1;
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x[2] = (word16)t2;
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}
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x[0] = idea_mult(x[0], idea->skey[skey_idx++]);
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out[0] = (x[0] >> 8) & 0xFF;
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out[1] = x[0] & 0xFF;
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x[2] = ((word32)x[2] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
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out[2] = (x[2] >> 8) & 0xFF;
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out[3] = x[2] & 0xFF;
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x[1] = ((word32)x[1] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
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out[4] = (x[1] >> 8) & 0xFF;
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out[5] = x[1] & 0xFF;
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x[3] = idea_mult(x[3], idea->skey[skey_idx++]);
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out[6] = (x[3] >> 8) & 0xFF;
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out[7] = x[3] & 0xFF;
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return 0;
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}
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int wc_IdeaCbcEncrypt(Idea *idea, byte* out, const byte* in, word32 len)
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{
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int blocks;
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int ret;
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if (idea == NULL || out == NULL || in == NULL)
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return BAD_FUNC_ARG;
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blocks = len / IDEA_BLOCK_SIZE;
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while (blocks--) {
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xorbuf((byte*)idea->reg, in, IDEA_BLOCK_SIZE);
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ret = wc_IdeaCipher(idea, (byte*)idea->reg, (byte*)idea->reg);
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if (ret != 0) {
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return ret;
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}
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XMEMCPY(out, idea->reg, IDEA_BLOCK_SIZE);
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out += IDEA_BLOCK_SIZE;
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in += IDEA_BLOCK_SIZE;
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}
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return 0;
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}
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int wc_IdeaCbcDecrypt(Idea *idea, byte* out, const byte* in, word32 len)
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{
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int blocks;
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int ret;
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if (idea == NULL || out == NULL || in == NULL)
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return BAD_FUNC_ARG;
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blocks = len / IDEA_BLOCK_SIZE;
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while (blocks--) {
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XMEMCPY((byte*)idea->tmp, in, IDEA_BLOCK_SIZE);
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ret = wc_IdeaCipher(idea, out, (byte*)idea->tmp);
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if (ret != 0) {
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return ret;
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}
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xorbuf(out, (byte*)idea->reg, IDEA_BLOCK_SIZE);
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XMEMCPY(idea->reg, idea->tmp, IDEA_BLOCK_SIZE);
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out += IDEA_BLOCK_SIZE;
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in += IDEA_BLOCK_SIZE;
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}
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return 0;
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}
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#endif /* HAVE_IDEA */
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