mirror of
https://github.com/Laupetin/OpenAssetTools.git
synced 2025-04-22 09:05:44 +00:00
146 lines
6.2 KiB
C
146 lines
6.2 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_dbl_point.c
|
|
ECC Crypto, Tom St Denis
|
|
*/
|
|
|
|
#if defined(LTC_MECC) && (!defined(LTC_MECC_ACCEL) || defined(LTM_DESC))
|
|
|
|
/**
|
|
Double an ECC point
|
|
@param P The point to double
|
|
@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_dbl_point(ecc_point *P, ecc_point *R, void *modulus, void *mp)
|
|
{
|
|
void *t1, *t2;
|
|
int err;
|
|
|
|
LTC_ARGCHK(P != NULL);
|
|
LTC_ARGCHK(R != NULL);
|
|
LTC_ARGCHK(modulus != NULL);
|
|
LTC_ARGCHK(mp != NULL);
|
|
|
|
if ((err = mp_init_multi(&t1, &t2, NULL)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
|
|
if (P != R) {
|
|
if ((err = mp_copy(P->x, R->x)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_copy(P->y, R->y)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_copy(P->z, R->z)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* t1 = Z * Z */
|
|
if ((err = mp_sqr(R->z, t1)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* Z = Y * Z */
|
|
if ((err = mp_mul(R->z, R->y, R->z)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(R->z, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* Z = 2Z */
|
|
if ((err = mp_add(R->z, R->z, R->z)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(R->z, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(R->z, modulus, R->z)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* T2 = X - T1 */
|
|
if ((err = mp_sub(R->x, t1, 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; }
|
|
}
|
|
/* T1 = X + T1 */
|
|
if ((err = mp_add(t1, R->x, t1)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(t1, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(t1, modulus, t1)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* T2 = T1 * T2 */
|
|
if ((err = mp_mul(t1, t2, t2)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T1 = 2T2 */
|
|
if ((err = mp_add(t2, t2, 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 = T1 + T2 */
|
|
if ((err = mp_add(t1, t2, t1)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(t1, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(t1, modulus, t1)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* Y = 2Y */
|
|
if ((err = mp_add(R->y, R->y, R->y)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp(R->y, modulus) != LTC_MP_LT) {
|
|
if ((err = mp_sub(R->y, modulus, R->y)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* Y = Y * Y */
|
|
if ((err = mp_sqr(R->y, R->y)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(R->y, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T2 = Y * Y */
|
|
if ((err = mp_sqr(R->y, t2)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* T2 = T2/2 */
|
|
if (mp_isodd(t2)) {
|
|
if ((err = mp_add(t2, modulus, t2)) != CRYPT_OK) { goto done; }
|
|
}
|
|
if ((err = mp_div_2(t2, t2)) != CRYPT_OK) { goto done; }
|
|
/* Y = Y * X */
|
|
if ((err = mp_mul(R->y, R->x, R->y)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(R->y, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
|
|
/* X = T1 * T1 */
|
|
if ((err = mp_sqr(t1, R->x)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(R->x, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* X = X - Y */
|
|
if ((err = mp_sub(R->x, R->y, R->x)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(R->x, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(R->x, modulus, R->x)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* X = X - Y */
|
|
if ((err = mp_sub(R->x, R->y, R->x)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(R->x, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(R->x, modulus, R->x)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
/* Y = Y - X */
|
|
if ((err = mp_sub(R->y, R->x, R->y)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(R->y, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(R->y, modulus, R->y)) != CRYPT_OK) { goto done; }
|
|
}
|
|
/* Y = Y * T1 */
|
|
if ((err = mp_mul(R->y, t1, R->y)) != CRYPT_OK) { goto done; }
|
|
if ((err = mp_montgomery_reduce(R->y, modulus, mp)) != CRYPT_OK) { goto done; }
|
|
/* Y = Y - T2 */
|
|
if ((err = mp_sub(R->y, t2, R->y)) != CRYPT_OK) { goto done; }
|
|
if (mp_cmp_d(R->y, 0) == LTC_MP_LT) {
|
|
if ((err = mp_add(R->y, modulus, R->y)) != CRYPT_OK) { goto done; }
|
|
}
|
|
|
|
err = CRYPT_OK;
|
|
done:
|
|
mp_clear_multi(t1, t2, NULL);
|
|
return err;
|
|
}
|
|
#endif
|
|
/* ref: HEAD -> master, tag: v1.18.2 */
|
|
/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
|
|
/* commit time: 2018-07-01 22:49:01 +0200 */
|
|
|