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- /* idea.c
- *
- * Copyright (C) 2006-2020 wolfSSL Inc.
- *
- * This file is part of wolfSSL.
- *
- * wolfSSL 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.
- *
- * wolfSSL 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 Street, Fifth Floor, Boston, MA 02110-1335, USA
- */
- #ifdef HAVE_CONFIG_H
- #include <config.h>
- #endif
- #include <wolfssl/wolfcrypt/settings.h>
- #ifdef HAVE_IDEA
- #include <wolfssl/wolfcrypt/idea.h>
- #include <wolfssl/wolfcrypt/error-crypt.h>
- #include <wolfssl/wolfcrypt/logging.h>
- #ifdef NO_INLINE
- #include <wolfssl/wolfcrypt/misc.h>
- #else
- #define WOLFSSL_MISC_INCLUDED
- #include <wolfcrypt/src/misc.c>
- #endif
- /* multiplication of x and y modulo 2^16+1
- * IDEA specify a special case when an entry value is 0 ( x or y)
- * then it must be replaced by 2^16
- */
- static WC_INLINE word16 idea_mult(word16 x, word16 y)
- {
- long mul, res;
- mul = (long)x * (long)y;
- if (mul) {
- res = (mul & IDEA_MASK) - ((word32)mul >> 16);
- if (res <= 0)
- res += IDEA_MODULO;
- return (word16) (res & IDEA_MASK);
- }
- if (!x)
- return ((IDEA_MODULO - y) & IDEA_MASK);
- /* !y */
- return ((IDEA_MODULO - x) & IDEA_MASK);
- }
- /* compute 1/a modulo 2^16+1 using Extended euclidean algorithm
- * adapted from fp_invmod */
- static WC_INLINE word16 idea_invmod(word16 x)
- {
- int u, v, b, d;
- if (x <= 1)
- return x;
- u = IDEA_MODULO;
- v = x;
- d = 1;
- b = 0;
- do {
- while (!(u & 1)) {
- u >>= 1;
- if (b & 1)
- b -= IDEA_MODULO;
- b >>= 1;
- }
- while (!(v & 1)) {
- v >>= 1;
- if (d & 1) {
- d -= IDEA_MODULO;
- }
- d >>= 1;
- }
- if (u >= v) {
- u -= v;
- b -= d;
- } else {
- v -= u;
- d -= b;
- }
- } while (u != 0);
- /* d is now the inverse, put positive value if required */
- while (d < 0)
- d += IDEA_MODULO;
- /* d must be < IDEA_MODULO */
- while (d >= (int)IDEA_MODULO)
- d -= IDEA_MODULO;
- return (word16)(d & IDEA_MASK);
- }
- /* generate the 52 16-bits key sub-blocks from the 128 key */
- int wc_IdeaSetKey(Idea *idea, const byte* key, word16 keySz,
- const byte *iv, int dir)
- {
- word16 idx = 0;
- word32 t;
- short i;
- if (idea == NULL || key == NULL || keySz != IDEA_KEY_SIZE ||
- (dir != IDEA_ENCRYPTION && dir != IDEA_DECRYPTION))
- return BAD_FUNC_ARG;
- /* initial key schedule for 0 -> 7 */
- for (i = 0; i < IDEA_ROUNDS; i++) {
- idea->skey[i] = (word16)key[idx++] << 8;
- idea->skey[i] |= (word16)key[idx++];
- }
- /* shift phase key schedule for 8 -> 51 */
- for (i = IDEA_ROUNDS; i < IDEA_SK_NUM; i++) {
- t = (word32)idea->skey[((i+1) & 7) ? i-7 : i-15] << 9;
- t |= (word32)idea->skey[((i+2) & 7) < 2 ? i-14 : i-6] >> 7;
- idea->skey[i] = (word16)(t & IDEA_MASK);
- }
- /* compute decryption key from encryption key */
- if (dir == IDEA_DECRYPTION) {
- word16 enckey[IDEA_SK_NUM];
- /* put encryption key in tmp buffer */
- XMEMCPY(enckey, idea->skey, sizeof(idea->skey));
- idx = 0;
- idea->skey[6*IDEA_ROUNDS] = idea_invmod(enckey[idx++]);
- idea->skey[6*IDEA_ROUNDS+1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
- idea->skey[6*IDEA_ROUNDS+2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
- idea->skey[6*IDEA_ROUNDS+3] = idea_invmod(enckey[idx++]);
- for (i = 6*(IDEA_ROUNDS-1); i >= 0; i -= 6) {
- idea->skey[i+4] = enckey[idx++];
- idea->skey[i+5] = enckey[idx++];
- idea->skey[i] = idea_invmod(enckey[idx++]);
- if (i) {
- idea->skey[i+2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
- idea->skey[i+1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
- }
- else {
- idea->skey[1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
- idea->skey[2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
- }
- idea->skey[i+3] = idea_invmod(enckey[idx++]);
- }
- /* erase temporary buffer */
- ForceZero(enckey, sizeof(enckey));
- }
- /* set the iv */
- return wc_IdeaSetIV(idea, iv);
- }
- /* set the IV in the Idea key structure */
- int wc_IdeaSetIV(Idea *idea, const byte* iv)
- {
- if (idea == NULL)
- return BAD_FUNC_ARG;
- if (iv != NULL)
- XMEMCPY(idea->reg, iv, IDEA_BLOCK_SIZE);
- else
- XMEMSET(idea->reg, 0, IDEA_BLOCK_SIZE);
- return 0;
- }
- /* encryption/decryption for a block (64 bits)
- */
- int wc_IdeaCipher(Idea *idea, byte* out, const byte* in)
- {
- word32 t1, t2;
- word16 i, skey_idx = 0, idx = 0;
- word16 x[4];
- if (idea == NULL || out == NULL || in == NULL) {
- return BAD_FUNC_ARG;
- }
- /* put input byte block in word16 */
- for (i = 0; i < IDEA_BLOCK_SIZE/2; i++) {
- x[i] = (word16)in[idx++] << 8;
- x[i] |= (word16)in[idx++];
- }
- for (i = 0; i < IDEA_ROUNDS; i++) {
- x[0] = idea_mult(x[0], idea->skey[skey_idx++]);
- x[1] = ((word32)x[1] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
- x[2] = ((word32)x[2] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
- x[3] = idea_mult(x[3], idea->skey[skey_idx++]);
- t2 = x[0] ^ x[2];
- t2 = idea_mult((word16)t2, idea->skey[skey_idx++]);
- t1 = (t2 + (x[1] ^ x[3])) & IDEA_MASK;
- t1 = idea_mult((word16)t1, idea->skey[skey_idx++]);
- t2 = (t1 + t2) & IDEA_MASK;
- x[0] ^= t1;
- x[3] ^= t2;
- t2 ^= x[1];
- x[1] = x[2] ^ (word16)t1;
- x[2] = (word16)t2;
- }
- x[0] = idea_mult(x[0], idea->skey[skey_idx++]);
- out[0] = (x[0] >> 8) & 0xFF;
- out[1] = x[0] & 0xFF;
- x[2] = ((word32)x[2] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
- out[2] = (x[2] >> 8) & 0xFF;
- out[3] = x[2] & 0xFF;
- x[1] = ((word32)x[1] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
- out[4] = (x[1] >> 8) & 0xFF;
- out[5] = x[1] & 0xFF;
- x[3] = idea_mult(x[3], idea->skey[skey_idx++]);
- out[6] = (x[3] >> 8) & 0xFF;
- out[7] = x[3] & 0xFF;
- return 0;
- }
- int wc_IdeaCbcEncrypt(Idea *idea, byte* out, const byte* in, word32 len)
- {
- int blocks;
- int ret;
- if (idea == NULL || out == NULL || in == NULL)
- return BAD_FUNC_ARG;
- blocks = len / IDEA_BLOCK_SIZE;
- while (blocks--) {
- xorbuf((byte*)idea->reg, in, IDEA_BLOCK_SIZE);
- ret = wc_IdeaCipher(idea, (byte*)idea->reg, (byte*)idea->reg);
- if (ret != 0) {
- return ret;
- }
- XMEMCPY(out, idea->reg, IDEA_BLOCK_SIZE);
- out += IDEA_BLOCK_SIZE;
- in += IDEA_BLOCK_SIZE;
- }
- return 0;
- }
- int wc_IdeaCbcDecrypt(Idea *idea, byte* out, const byte* in, word32 len)
- {
- int blocks;
- int ret;
- if (idea == NULL || out == NULL || in == NULL)
- return BAD_FUNC_ARG;
- blocks = len / IDEA_BLOCK_SIZE;
- while (blocks--) {
- XMEMCPY((byte*)idea->tmp, in, IDEA_BLOCK_SIZE);
- ret = wc_IdeaCipher(idea, out, (byte*)idea->tmp);
- if (ret != 0) {
- return ret;
- }
- xorbuf(out, (byte*)idea->reg, IDEA_BLOCK_SIZE);
- XMEMCPY(idea->reg, idea->tmp, IDEA_BLOCK_SIZE);
- out += IDEA_BLOCK_SIZE;
- in += IDEA_BLOCK_SIZE;
- }
- return 0;
- }
- #endif /* HAVE_IDEA */
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