mirror of
https://github.com/Laupetin/OpenAssetTools.git
synced 2025-04-22 00:55:45 +00:00
195 lines
8.6 KiB
C
195 lines
8.6 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
|
|
*
|
|
* LibTomCrypt is a library that provides various cryptographic
|
|
* algorithms in a highly modular and flexible manner.
|
|
*
|
|
* The library is free for all purposes without any express
|
|
* guarantee it works.
|
|
*/
|
|
|
|
/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b
|
|
*
|
|
* All curves taken from NIST recommendation paper of July 1999
|
|
* Available at http://csrc.nist.gov/cryptval/dss.htm
|
|
*/
|
|
#include "tomcrypt.h"
|
|
|
|
/**
|
|
@file ltc_ecc_projective_add_point.c
|
|
ECC Crypto, Tom St Denis
|
|
*/
|
|
|
|
#if defined(LTC_MECC) && (!defined(LTC_MECC_ACCEL) || defined(LTM_DESC))
|
|
|
|
/**
|
|
Add two ECC points
|
|
@param P The point to add
|
|
@param Q The point to add
|
|
@param R [out] The destination of the double
|
|
@param modulus The modulus of the field the ECC curve is in
|
|
@param mp The "b" value from montgomery_setup()
|
|
@return CRYPT_OK on success
|
|
*/
|
|
int ltc_ecc_projective_add_point(ecc_point *P, ecc_point *Q, ecc_point *R, void *modulus, void *mp)
|
|
{
|
|
void *t1, *t2, *x, *y, *z;
|
|
int err;
|
|
|
|
LTC_ARGCHK(P != NULL);
|
|
LTC_ARGCHK(Q != NULL);
|
|
LTC_ARGCHK(R != NULL);
|
|
LTC_ARGCHK(modulus != NULL);
|
|
LTC_ARGCHK(mp != NULL);
|
|
|
|
if ((err = mp_init_multi(&t1, &t2, &x, &y, &z, NULL)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
|
|
/* should we dbl instead? */
|
|
if ((err = mp_sub(modulus, Q->y, t1)) != CRYPT_OK) { goto done; }
|
|
|
|
if ( (mp_cmp(P->x, Q->x) == LTC_MP_EQ) &&
|
|
(Q->z != NULL && mp_cmp(P->z, Q->z) == LTC_MP_EQ) &&
|
|
(mp_cmp(P->y, Q->y) == LTC_MP_EQ || mp_cmp(P->y, t1) == LTC_MP_EQ)) {
|
|
mp_clear_multi(t1, t2, x, y, z, NULL);
|
|
return ltc_ecc_projective_dbl_point(P, R, modulus, mp);
|
|
}
|
|
|
|
if ((err = mp_copy(P->x, x)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_copy(P->y, y)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_copy(P->z, z)) != CRYPT_OK) { goto done; }
|
|
|
|
/* if Z is one then these are no-operations */
|
|
if (Q->z != NULL) {
|
|
/* T1 = Z' * Z' */
|
|
if ((err = mp_sqr(Q->z, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* X = X * T1 */
|
|
if ((err = mp_mul(t1, x, x)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(x, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T1 = Z' * T1 */
|
|
if ((err = mp_mul(Q->z, t1, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* Y = Y * T1 */
|
|
if ((err = mp_mul(t1, y, y)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(y, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* T1 = Z*Z */
|
|
if ((err = mp_sqr(z, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T2 = X' * T1 */
|
|
if ((err = mp_mul(Q->x, t1, t2)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T1 = Z * T1 */
|
|
if ((err = mp_mul(z, t1, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T1 = Y' * T1 */
|
|
if ((err = mp_mul(Q->y, t1, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
|
|
/* Y = Y - T1 */
|
|
if ((err = mp_sub(y, t1, y)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(y, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(y, modulus, y)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* T1 = 2T1 */
|
|
if ((err = mp_add(t1, t1, t1)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(t1, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(t1, modulus, t1)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* T1 = Y + T1 */
|
|
if ((err = mp_add(t1, y, t1)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(t1, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(t1, modulus, t1)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* X = X - T2 */
|
|
if ((err = mp_sub(x, t2, x)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(x, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(x, modulus, x)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* T2 = 2T2 */
|
|
if ((err = mp_add(t2, t2, t2)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(t2, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(t2, modulus, t2)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* T2 = X + T2 */
|
|
if ((err = mp_add(t2, x, t2)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(t2, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(t2, modulus, t2)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* if Z' != 1 */
|
|
if (Q->z != NULL) {
|
|
/* Z = Z * Z' */
|
|
if ((err = mp_mul(z, Q->z, z)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(z, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* Z = Z * X */
|
|
if ((err = mp_mul(z, x, z)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(z, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
|
|
/* T1 = T1 * X */
|
|
if ((err = mp_mul(t1, x, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* X = X * X */
|
|
if ((err = mp_sqr(x, x)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(x, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T2 = T2 * x */
|
|
if ((err = mp_mul(t2, x, t2)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T1 = T1 * X */
|
|
if ((err = mp_mul(t1, x, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
|
|
/* X = Y*Y */
|
|
if ((err = mp_sqr(y, x)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(x, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* X = X - T2 */
|
|
if ((err = mp_sub(x, t2, x)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(x, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(x, modulus, x)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* T2 = T2 - X */
|
|
if ((err = mp_sub(t2, x, t2)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(t2, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(t2, modulus, t2)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* T2 = T2 - X */
|
|
if ((err = mp_sub(t2, x, t2)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(t2, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(t2, modulus, t2)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* T2 = T2 * Y */
|
|
if ((err = mp_mul(t2, y, t2)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* Y = T2 - T1 */
|
|
if ((err = mp_sub(t2, t1, y)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(y, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(y, modulus, y)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* Y = Y/2 */
|
|
if (mp_isodd(y)) {
|
|
if ((err = mp_add(y, modulus, y)) != CRYPT_OK) { goto done; }
|
|
}
|
|
if ((err = mp_div_2(y, y)) != CRYPT_OK) { goto done; }
|
|
|
|
if ((err = mp_copy(x, R->x)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_copy(y, R->y)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_copy(z, R->z)) != CRYPT_OK) { goto done; }
|
|
|
|
err = CRYPT_OK;
|
|
done:
|
|
mp_clear_multi(t1, t2, x, y, z, NULL);
|
|
return err;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* ref: HEAD -> master, tag: v1.18.2 */
|
|
/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
|
|
/* commit time: 2018-07-01 22:49:01 +0200 */
|
|
|