diff options
| -rw-r--r-- | networking/tls_sp_c32.c | 58 |
1 files changed, 21 insertions, 37 deletions
diff --git a/networking/tls_sp_c32.c b/networking/tls_sp_c32.c index 8527e78..72a3be5 100644 --- a/networking/tls_sp_c32.c +++ b/networking/tls_sp_c32.c @@ -203,26 +203,12 @@ static void sp_256_add_10(sp_digit* r, const sp_digit* a, const sp_digit* b) r[i] = a[i] + b[i]; } -/* Conditionally add a and b using the mask m. - * m is -1 to add and 0 when not. - */ -static void sp_256_cond_add_10(sp_digit* r, const sp_digit* a, - const sp_digit* b, const sp_digit m) -{ - int i; - for (i = 0; i < 10; i++) - r[i] = a[i] + (b[i] & m); -} - -/* Conditionally subtract b from a using the mask m. - * m is -1 to subtract and 0 when not. - */ -static void sp_256_cond_sub_10(sp_digit* r, const sp_digit* a, - const sp_digit* b, const sp_digit m) +/* Sub b from a into r. (r = a - b) */ +static void sp_256_sub_10(sp_digit* r, const sp_digit* a, const sp_digit* b) { int i; for (i = 0; i < 10; i++) - r[i] = a[i] - (b[i] & m); + r[i] = a[i] - b[i]; } /* Shift number left one bit. Bottom bit is lost. */ @@ -352,7 +338,8 @@ static void sp_256_mul_add_10(sp_digit* r, const sp_digit* a, sp_digit b) /* Divide the number by 2 mod the modulus (prime). (r = a / 2 % m) */ static void sp_256_div2_10(sp_digit* r, const sp_digit* a, const sp_digit* m) { - sp_256_cond_add_10(r, a, m, 0 - (a[0] & 1)); + if (a[0] & 1) + sp_256_add_10(r, a, m); sp_256_norm_10(r); sp_256_rshift1_10(r, r); } @@ -382,7 +369,8 @@ static void sp_256_mont_add_10(sp_digit* r, const sp_digit* a, const sp_digit* b { sp_256_add_10(r, a, b); sp_256_norm_10(r); - sp_256_cond_sub_10(r, r, m, 0 - ((r[9] >> 22) > 0)); + if ((r[9] >> 22) > 0) + sp_256_sub_10(r, r, m); sp_256_norm_10(r); } @@ -391,7 +379,8 @@ static void sp_256_mont_dbl_10(sp_digit* r, const sp_digit* a, const sp_digit* m { sp_256_add_10(r, a, a); sp_256_norm_10(r); - sp_256_cond_sub_10(r, r, m, 0 - ((r[9] >> 22) > 0)); + if ((r[9] >> 22) > 0) + sp_256_sub_10(r, r, m); sp_256_norm_10(r); } @@ -400,28 +389,23 @@ static void sp_256_mont_tpl_10(sp_digit* r, const sp_digit* a, const sp_digit* m { sp_256_add_10(r, a, a); sp_256_norm_10(r); - sp_256_cond_sub_10(r, r, m, 0 - ((r[9] >> 22) > 0)); + if ((r[9] >> 22) > 0) + sp_256_sub_10(r, r, m); sp_256_norm_10(r); sp_256_add_10(r, r, a); sp_256_norm_10(r); - sp_256_cond_sub_10(r, r, m, 0 - ((r[9] >> 22) > 0)); + if ((r[9] >> 22) > 0) + sp_256_sub_10(r, r, m); sp_256_norm_10(r); } -/* Sub b from a into r. (r = a - b) */ -static void sp_256_sub_10(sp_digit* r, const sp_digit* a, const sp_digit* b) -{ - int i; - for (i = 0; i < 10; i++) - r[i] = a[i] - b[i]; -} - /* Subtract two Montgomery form numbers (r = a - b % m) */ static void sp_256_mont_sub_10(sp_digit* r, const sp_digit* a, const sp_digit* b, const sp_digit* m) { sp_256_sub_10(r, a, b); - sp_256_cond_add_10(r, r, m, r[9] >> 22); + if (r[9] >> 22) + sp_256_add_10(r, r, m); sp_256_norm_10(r); } @@ -460,7 +444,8 @@ static void sp_256_mont_reduce_10(sp_digit* a, const sp_digit* m, sp_digit mp) } sp_256_mont_shift_10(a, a); - sp_256_cond_sub_10(a, a, m, 0 - ((a[9] >> 22) > 0)); + if ((a[9] >> 22) > 0) + sp_256_sub_10(a, a, m); sp_256_norm_10(a); } @@ -590,7 +575,6 @@ static void sp_256_map_10(sp_point* r, sp_point* p) { sp_digit t1[2*10]; sp_digit t2[2*10]; - int32_t n; sp_256_mont_inv_10(t1, p->z); @@ -602,8 +586,8 @@ static void sp_256_map_10(sp_point* r, sp_point* p) memset(r->x + 10, 0, sizeof(r->x) / 2); sp_256_mont_reduce_10(r->x, p256_mod, p256_mp_mod); /* Reduce x to less than modulus */ - n = sp_256_cmp_10(r->x, p256_mod); - sp_256_cond_sub_10(r->x, r->x, p256_mod, 0 - (n >= 0)); + if (sp_256_cmp_10(r->x, p256_mod) >= 0) + sp_256_sub_10(r->x, r->x, p256_mod); sp_256_norm_10(r->x); /* y /= z^3 */ @@ -611,8 +595,8 @@ static void sp_256_map_10(sp_point* r, sp_point* p) memset(r->y + 10, 0, sizeof(r->y) / 2); sp_256_mont_reduce_10(r->y, p256_mod, p256_mp_mod); /* Reduce y to less than modulus */ - n = sp_256_cmp_10(r->y, p256_mod); - sp_256_cond_sub_10(r->y, r->y, p256_mod, 0 - (n >= 0)); + if (sp_256_cmp_10(r->y, p256_mod) >= 0) + sp_256_sub_10(r->y, r->y, p256_mod); sp_256_norm_10(r->y); memset(r->z, 0, sizeof(r->z)); |