void ep_curve_set_endom(const fp_t b, const ep_t g, const bn_t r, const bn_t h,
const fp_t beta, const bn_t l) {
int bits = bn_bits(r);
ctx_t *ctx = core_get();
ctx->ep_is_endom = 1;
ctx->ep_is_super = 0;
fp_zero(ctx->ep_a);
fp_copy(ctx->ep_b, b);
detect_opt(&(ctx->ep_opt_a), ctx->ep_a);
detect_opt(&(ctx->ep_opt_b), ctx->ep_b);
#if EP_MUL == LWNAF || EP_FIX == COMBS || EP_FIX == LWNAF || EP_SIM == INTER || !defined(STRIP)
fp_copy(ctx->beta, beta);
bn_gcd_ext_mid(&(ctx->ep_v1[1]), &(ctx->ep_v1[2]), &(ctx->ep_v2[1]),
&(ctx->ep_v2[2]), l, r);
/* l = v1[1] * v2[2] - v1[2] * v2[1], r = l / 2. */
bn_mul(&(ctx->ep_v1[0]), &(ctx->ep_v1[1]), &(ctx->ep_v2[2]));
bn_mul(&(ctx->ep_v2[0]), &(ctx->ep_v1[2]), &(ctx->ep_v2[1]));
bn_sub(&(ctx->ep_r), &(ctx->ep_v1[0]), &(ctx->ep_v2[0]));
bn_hlv(&(ctx->ep_r), &(ctx->ep_r));
/* v1[0] = round(v2[2] * 2^|n| / l). */
bn_lsh(&(ctx->ep_v1[0]), &(ctx->ep_v2[2]), bits + 1);
if (bn_sign(&(ctx->ep_v1[0])) == BN_POS) {
bn_add(&(ctx->ep_v1[0]), &(ctx->ep_v1[0]), &(ctx->ep_r));
} else {
bn_sub(&(ctx->ep_v1[0]), &(ctx->ep_v1[0]), &(ctx->ep_r));
}
bn_dbl(&(ctx->ep_r), &(ctx->ep_r));
bn_div(&(ctx->ep_v1[0]), &(ctx->ep_v1[0]), &(ctx->ep_r));
if (bn_sign(&ctx->ep_v1[0]) == BN_NEG) {
bn_add_dig(&(ctx->ep_v1[0]), &(ctx->ep_v1[0]), 1);
}
/* v2[0] = round(v1[2] * 2^|n| / l). */
bn_lsh(&(ctx->ep_v2[0]), &(ctx->ep_v1[2]), bits + 1);
if (bn_sign(&(ctx->ep_v2[0])) == BN_POS) {
bn_add(&(ctx->ep_v2[0]), &(ctx->ep_v2[0]), &(ctx->ep_r));
} else {
bn_sub(&(ctx->ep_v2[0]), &(ctx->ep_v2[0]), &(ctx->ep_r));
}
bn_div(&(ctx->ep_v2[0]), &(ctx->ep_v2[0]), &(ctx->ep_r));
if (bn_sign(&ctx->ep_v2[0]) == BN_NEG) {
bn_add_dig(&(ctx->ep_v2[0]), &(ctx->ep_v2[0]), 1);
}
bn_neg(&(ctx->ep_v2[0]), &(ctx->ep_v2[0]));
#endif
ep_norm(&(ctx->ep_g), g);
bn_copy(&(ctx->ep_r), r);
bn_copy(&(ctx->ep_h), h);
#if defined(EP_PRECO)
ep_mul_pre((ep_t *)ep_curve_get_tab(), &(ctx->ep_g));
#endif
}
/**
* Precomputes additional parameters for Koblitz curves used by the w-TNAF
* multiplication algorithm.
*/
static void compute_kbltz(void) {
int u, i;
bn_t a, b, c;
bn_null(a);
bn_null(b);
bn_null(c);
TRY {
bn_new(a);
bn_new(b);
bn_new(c);
if (curve_opt_a == OPT_ZERO) {
u = -1;
} else {
u = 1;
}
bn_set_dig(a, 2);
bn_set_dig(b, 1);
if (u == -1) {
bn_neg(b, b);
}
for (i = 2; i <= FB_BITS; i++) {
bn_copy(c, b);
if (u == -1) {
bn_neg(b, b);
}
bn_dbl(a, a);
bn_sub(b, b, a);
bn_copy(a, c);
}
bn_copy(&curve_vm, b);
bn_zero(a);
bn_set_dig(b, 1);
for (i = 2; i <= FB_BITS; i++) {
bn_copy(c, b);
if (u == -1) {
bn_neg(b, b);
}
bn_dbl(a, a);
bn_sub(b, b, a);
bn_add_dig(b, b, 1);
bn_copy(a, c);
}
bn_copy(&curve_s0, b);
bn_zero(a);
bn_zero(b);
for (i = 2; i <= FB_BITS; i++) {
bn_copy(c, b);
if (u == -1) {
bn_neg(b, b);
}
bn_dbl(a, a);
bn_sub(b, b, a);
bn_sub_dig(b, b, 1);
bn_copy(a, c);
}
bn_copy(&curve_s1, b);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(a);
bn_free(b);
bn_free(c);
}
}
void bn_gen_prime_stron(bn_t a, int bits) {
dig_t i, j;
int found, k;
bn_t r, s, t;
bn_null(r);
bn_null(s);
bn_null(t);
TRY {
bn_new(r);
bn_new(s);
bn_new(t);
do {
do {
/* Generate two large primes r and s. */
bn_rand(s, BN_POS, bits / 2 - BN_DIGIT / 2);
bn_rand(t, BN_POS, bits / 2 - BN_DIGIT / 2);
} while (!bn_is_prime(s) || !bn_is_prime(t));
found = 1;
bn_rand(a, BN_POS, bits / 2 - bn_bits(t) - 1);
i = a->dp[0];
bn_dbl(t, t);
do {
/* Find first prime r = 2 * i * t + 1. */
bn_mul_dig(r, t, i);
bn_add_dig(r, r, 1);
i++;
if (bn_bits(r) > bits / 2 - 1) {
found = 0;
break;
}
} while (!bn_is_prime(r));
if (found == 0) {
continue;
}
/* Compute t = 2 * (s^(r-2) mod r) * s - 1. */
bn_sub_dig(t, r, 2);
#if BN_MOD != PMERS
bn_mxp(t, s, t, r);
#else
bn_exp(t, s, t, r);
#endif
bn_mul(t, t, s);
bn_dbl(t, t);
bn_sub_dig(t, t, 1);
k = bits - bn_bits(r);
k -= bn_bits(s);
bn_rand(a, BN_POS, k);
j = a->dp[0];
do {
/* Find first prime a = t + 2 * j * r * s. */
bn_mul(a, r, s);
bn_mul_dig(a, a, j);
bn_dbl(a, a);
bn_add(a, a, t);
j++;
if (bn_bits(a) > bits) {
found = 0;
break;
}
} while (!bn_is_prime(a));
} while (found == 0 && bn_bits(a) != bits);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(r);
bn_free(s);
bn_free(t);
}
}
void fp_param_set(int param) {
bn_t t0, t1, t2, p;
int f[10] = { 0 };
bn_null(t0);
bn_null(t1);
bn_null(t2);
bn_null(p);
/* Suppress possible unused parameter warning. */
(void) f;
TRY {
bn_new(t0);
bn_new(t1);
bn_new(t2);
bn_new(p);
core_get()->fp_id = param;
switch (param) {
#if FP_PRIME == 158
case BN_158:
/* x = 4000000031. */
fp_param_get_var(t0);
/* p = 36 * x^4 + 36 * x^3 + 24 * x^2 + 6 * x + 1. */
bn_set_dig(p, 1);
bn_mul_dig(t1, t0, 6);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 24);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul(t1, t1, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
bn_mul(t0, t0, t0);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
fp_prime_set_dense(p);
break;
#elif FP_PRIME == 160
case SECG_160:
/* p = 2^160 - 2^31 + 1. */
f[0] = -1;
f[1] = -31;
f[2] = 160;
fp_prime_set_pmers(f, 3);
break;
case SECG_160D:
/* p = 2^160 - 2^32 - 2^14 - 2^12 - 2^9 - 2^8 - 2^7 - 2^3 - 2^2 - 1.*/
f[0] = -1;
f[1] = -2;
f[2] = -3;
f[3] = -7;
f[4] = -8;
f[5] = -9;
f[6] = -12;
f[7] = -14;
f[8] = -32;
f[9] = 160;
fp_prime_set_pmers(f, 10);
break;
#elif FP_PRIME == 192
case NIST_192:
/* p = 2^192 - 2^64 - 1. */
f[0] = -1;
f[1] = -64;
f[2] = 192;
fp_prime_set_pmers(f, 3);
break;
case SECG_192:
/* p = 2^192 - 2^32 - 2^12 - 2^8 - 2^7 - 2^6 - 2^3 - 1.*/
f[0] = -1;
f[1] = -3;
f[2] = -6;
f[3] = -7;
f[4] = -8;
f[5] = -12;
f[6] = -32;
f[7] = 192;
fp_prime_set_pmers(f, 8);
break;
#elif FP_PRIME == 224
case NIST_224:
/* p = 2^224 - 2^96 + 1. */
f[0] = 1;
f[1] = -96;
f[2] = 224;
fp_prime_set_pmers(f, 3);
break;
case SECG_224:
/* p = 2^224 - 2^32 - 2^12 - 2^11 - 2^9 - 2^7 - 2^4 - 2 - 1.*/
f[0] = -1;
f[1] = -1;
f[2] = -4;
f[3] = -7;
f[4] = -9;
f[5] = -11;
f[6] = -12;
f[7] = -32;
f[8] = 224;
fp_prime_set_pmers(f, 9);
break;
#elif FP_PRIME == 254
case BN_254:
/* x = -4080000000000001. */
fp_param_get_var(t0);
/* p = 36 * x^4 + 36 * x^3 + 24 * x^2 + 6 * x + 1. */
bn_set_dig(p, 1);
bn_mul_dig(t1, t0, 6);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 24);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul(t1, t1, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
bn_mul(t0, t0, t0);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
fp_prime_set_dense(p);
break;
#elif FP_PRIME == 256
case NIST_256:
/* p = 2^256 - 2^224 + 2^192 + 2^96 - 1. */
f[0] = -1;
f[1] = 96;
f[2] = 192;
f[3] = -224;
f[4] = 256;
fp_prime_set_pmers(f, 5);
break;
case SECG_256:
/* p = 2^256 - 2^32 - 2^9 - 2^8 - 2^7 - 2^6 - 2^4 - 1. */
f[0] = -1;
f[1] = -4;
f[2] = -6;
f[3] = -7;
f[4] = -8;
f[5] = -9;
f[6] = -32;
f[7] = 256;
fp_prime_set_pmers(f, 8);
break;
case BN_256:
/* x = 6000000000001F2D. */
fp_param_get_var(t0);
/* p = 36 * x^4 + 36 * x^3 + 24 * x^2 + 6 * x + 1. */
bn_set_dig(p, 1);
bn_mul_dig(t1, t0, 6);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 24);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul(t1, t1, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
bn_mul(t0, t0, t0);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
fp_prime_set_dense(p);
break;
#elif FP_PRIME == 384
case NIST_384:
/* p = 2^384 - 2^128 - 2^96 + 2^32 - 1. */
f[0] = -1;
f[1] = 32;
f[2] = -96;
f[3] = -128;
f[4] = 384;
fp_prime_set_pmers(f, 5);
break;
#elif FP_PRIME == 477
case B24_477:
fp_param_get_var(t0);
/* p = (u - 1)^2 * (u^8 - u^4 + 1) div 3 + u. */
bn_sub_dig(p, t0, 1);
bn_sqr(p, p);
bn_sqr(t1, t0);
bn_sqr(t1, t1);
bn_sqr(t2, t1);
bn_sub(t2, t2, t1);
bn_add_dig(t2, t2, 1);
bn_mul(p, p, t2);
bn_div_dig(p, p, 3);
bn_add(p, p, t0);
fp_prime_set_dense(p);
break;
#elif FP_PRIME == 508
case KSS_508:
fp_param_get_var(t0);
/* h = (49*u^2 + 245 * u + 343)/3 */
bn_mul_dig(p, t0, 245);
bn_add_dig(p, p, 200);
bn_add_dig(p, p, 143);
bn_sqr(t1, t0);
bn_mul_dig(t2, t1, 49);
bn_add(p, p, t2);
bn_div_dig(p, p, 3);
/* n = (u^6 + 37 * u^3 + 343)/343. */
bn_mul(t1, t1, t0);
bn_mul_dig(t2, t1, 37);
bn_sqr(t1, t1);
bn_add(t2, t2, t1);
bn_add_dig(t2, t2, 200);
bn_add_dig(t2, t2, 143);
bn_div_dig(t2, t2, 49);
bn_div_dig(t2, t2, 7);
bn_mul(p, p, t2);
/* t = (u^4 + 16 * u + 7)/7. */
bn_mul_dig(t1, t0, 16);
bn_add_dig(t1, t1, 7);
bn_sqr(t2, t0);
bn_sqr(t2, t2);
bn_add(t2, t2, t1);
bn_div_dig(t2, t2, 7);
bn_add(p, p, t2);
bn_sub_dig(p, p, 1);
fp_prime_set_dense(p);
break;
#elif FP_PRIME == 521
case NIST_521:
/* p = 2^521 - 1. */
f[0] = -1;
f[1] = 521;
fp_prime_set_pmers(f, 2);
break;
#elif FP_PRIME == 638
case BN_638:
fp_param_get_var(t0);
/* p = 36 * x^4 + 36 * x^3 + 24 * x^2 + 6 * x + 1. */
bn_set_dig(p, 1);
bn_mul_dig(t1, t0, 6);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 24);
bn_add(p, p, t1);
bn_mul(t1, t0, t0);
bn_mul(t1, t1, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
bn_mul(t0, t0, t0);
bn_mul(t1, t0, t0);
bn_mul_dig(t1, t1, 36);
bn_add(p, p, t1);
fp_prime_set_dense(p);
break;
case B12_638:
fp_param_get_var(t0);
/* p = (x^2 - 2x + 1) * (x^4 - x^2 + 1)/3 + x. */
bn_sqr(t1, t0);
bn_sqr(p, t1);
bn_sub(p, p, t1);
bn_add_dig(p, p, 1);
bn_sub(t1, t1, t0);
bn_sub(t1, t1, t0);
bn_add_dig(t1, t1, 1);
bn_mul(p, p, t1);
bn_div_dig(p, p, 3);
bn_add(p, p, t0);
fp_prime_set_dense(p);
break;
#elif FP_PRIME == 1536
case SS_1536:
fp_param_get_var(t0);
bn_read_str(p, SS_P1536, strlen(SS_P1536), 16);
bn_mul(p, p, t0);
bn_dbl(p, p);
bn_sub_dig(p, p, 1);
fp_prime_set_dense(p);
break;
#else
default:
bn_gen_prime(p, FP_BITS);
fp_prime_set_dense(p);
core_get()->fp_id = 0;
break;
#endif
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(t0);
bn_free(t1);
bn_free(t2);
bn_free(p);
}
}
