?? ltc_ecc_projective_add_point.c
字號:
/* 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. * * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com *//* 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(MECC) && (!defined(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/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ltc_ecc_projective_add_point.c,v $ *//* $Revision: 1.13 $ *//* $Date: 2006/12/04 05:07:59 $ */?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -