int cp_ecss_ver(bn_t e, bn_t s, unsigned char *msg, int len, ec_t q) {
bn_t n, ev, rv;
ec_t p;
unsigned char hash[MD_LEN];
unsigned char m[len + EC_BYTES];
int result = 0;
bn_null(n);
bn_null(ev);
bn_null(rv);
ec_null(p);
TRY {
bn_new(n);
bn_new(ev);
bn_new(rv);
ec_new(p);
ec_curve_get_ord(n);
if (bn_sign(e) == BN_POS && bn_sign(s) == BN_POS && !bn_is_zero(s)) {
if (bn_cmp(e, n) == CMP_LT && bn_cmp(s, n) == CMP_LT) {
ec_mul_sim_gen(p, s, q, e);
ec_get_x(rv, p);
bn_mod(rv, rv, n);
memcpy(m, msg, len);
bn_write_bin(m + len, EC_BYTES, rv);
md_map(hash, m, len + EC_BYTES);
if (8 * MD_LEN > bn_bits(n)) {
len = CEIL(bn_bits(n), 8);
bn_read_bin(ev, hash, len);
bn_rsh(ev, ev, 8 * MD_LEN - bn_bits(n));
} else {
bn_read_bin(ev, hash, MD_LEN);
}
bn_mod(ev, ev, n);
result = dv_cmp_const(ev->dp, e->dp, MIN(ev->used, e->used));
result = (result == CMP_NE ? 0 : 1);
if (ev->used != e->used) {
result = 0;
}
}
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(n);
bn_free(ev);
bn_free(rv);
ec_free(p);
}
return result;
}
/**
* Multiplies and adds two prime elliptic curve points simultaneously,
* optionally choosing the first point as the generator depending on an optional
* table of precomputed points.
*
* @param[out] r - the result.
* @param[in] p - the first point to multiply.
* @param[in] k - the first integer.
* @param[in] q - the second point to multiply.
* @param[in] m - the second integer.
* @param[in] t - the pointer to the precomputed table.
*/
void ep_mul_sim_endom(ep_t r, const ep_t p, const bn_t k, const ep_t q,
const bn_t m, const ep_t *t) {
int len, len0, len1, len2, len3, i, n, sk0, sk1, sl0, sl1, w, g = 0;
int8_t naf0[FP_BITS + 1], naf1[FP_BITS + 1], *t0, *t1;
int8_t naf2[FP_BITS + 1], naf3[FP_BITS + 1], *t2, *t3;
bn_t k0, k1, l0, l1;
bn_t ord, v1[3], v2[3];
ep_t u;
ep_t tab0[1 << (EP_WIDTH - 2)];
ep_t tab1[1 << (EP_WIDTH - 2)];
bn_null(ord);
bn_null(k0);
bn_null(k1);
bn_null(l0);
bn_null(l1);
ep_null(u);
for (i = 0; i < (1 << (EP_WIDTH - 2)); i++) {
ep_null(tab0[i]);
ep_null(tab1[i]);
}
bn_new(ord);
bn_new(k0);
bn_new(k1);
bn_new(l0);
bn_new(l1);
ep_new(u);
TRY {
for (i = 0; i < 3; i++) {
bn_null(v1[i]);
bn_null(v2[i]);
bn_new(v1[i]);
bn_new(v2[i]);
}
ep_curve_get_ord(ord);
ep_curve_get_v1(v1);
ep_curve_get_v2(v2);
bn_rec_glv(k0, k1, k, ord, (const bn_t *)v1, (const bn_t *)v2);
sk0 = bn_sign(k0);
sk1 = bn_sign(k1);
bn_abs(k0, k0);
bn_abs(k1, k1);
bn_rec_glv(l0, l1, m, ord, (const bn_t *)v1, (const bn_t *)v2);
sl0 = bn_sign(l0);
sl1 = bn_sign(l1);
bn_abs(l0, l0);
bn_abs(l1, l1);
g = (t == NULL ? 0 : 1);
if (!g) {
for (i = 0; i < (1 << (EP_WIDTH - 2)); i++) {
ep_new(tab0[i]);
}
ep_tab(tab0, p, EP_WIDTH);
t = (const ep_t *)tab0;
}
/* Prepare the precomputation table. */
for (i = 0; i < (1 << (EP_WIDTH - 2)); i++) {
ep_new(tab1[i]);
}
/* Compute the precomputation table. */
ep_tab(tab1, q, EP_WIDTH);
/* Compute the w-TNAF representation of k and l */
if (g) {
w = EP_DEPTH;
} else {
w = EP_WIDTH;
}
len0 = len1 = len2 = len3 = FP_BITS + 1;
bn_rec_naf(naf0, &len0, k0, w);
bn_rec_naf(naf1, &len1, k1, w);
bn_rec_naf(naf2, &len2, l0, EP_WIDTH);
bn_rec_naf(naf3, &len3, l1, EP_WIDTH);
len = MAX(MAX(len0, len1), MAX(len2, len3));
t0 = naf0 + len - 1;
t1 = naf1 + len - 1;
t2 = naf2 + len - 1;
t3 = naf3 + len - 1;
for (i = len0; i < len; i++) {
naf0[i] = 0;
}
for (i = len1; i < len; i++) {
naf1[i] = 0;
}
for (i = len2; i < len; i++) {
naf2[i] = 0;
}
for (i = len3; i < len; i++) {
naf3[i] = 0;
}
ep_set_infty(r);
for (i = len - 1; i >= 0; i--, t0--, t1--, t2--, t3--) {
ep_dbl(r, r);
n = *t0;
if (n > 0) {
if (sk0 == BN_POS) {
ep_add(r, r, t[n / 2]);
} else {
ep_sub(r, r, t[n / 2]);
}
}
if (n < 0) {
if (sk0 == BN_POS) {
ep_sub(r, r, t[-n / 2]);
} else {
ep_add(r, r, t[-n / 2]);
}
}
n = *t1;
if (n > 0) {
ep_copy(u, t[n / 2]);
fp_mul(u->x, u->x, ep_curve_get_beta());
if (sk1 == BN_NEG) {
ep_neg(u, u);
}
ep_add(r, r, u);
}
if (n < 0) {
ep_copy(u, t[-n / 2]);
fp_mul(u->x, u->x, ep_curve_get_beta());
if (sk1 == BN_NEG) {
ep_neg(u, u);
}
ep_sub(r, r, u);
}
n = *t2;
if (n > 0) {
if (sl0 == BN_POS) {
ep_add(r, r, tab1[n / 2]);
} else {
ep_sub(r, r, tab1[n / 2]);
}
}
if (n < 0) {
if (sl0 == BN_POS) {
ep_sub(r, r, tab1[-n / 2]);
} else {
ep_add(r, r, tab1[-n / 2]);
}
}
n = *t3;
if (n > 0) {
ep_copy(u, tab1[n / 2]);
fp_mul(u->x, u->x, ep_curve_get_beta());
if (sl1 == BN_NEG) {
ep_neg(u, u);
}
ep_add(r, r, u);
}
if (n < 0) {
ep_copy(u, tab1[-n / 2]);
fp_mul(u->x, u->x, ep_curve_get_beta());
if (sl1 == BN_NEG) {
ep_neg(u, u);
}
ep_sub(r, r, u);
}
}
/* Convert r to affine coordinates. */
ep_norm(r, r);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(ord);
bn_free(k0);
bn_free(k1);
bn_free(l0);
bn_free(l1);
ep_free(u);
if (!g) {
for (i = 0; i < 1 << (EP_WIDTH - 2); i++) {
ep_free(tab0[i]);
}
}
/* Free the precomputation tables. */
for (i = 0; i < 1 << (EP_WIDTH - 2); i++) {
ep_free(tab1[i]);
}
for (i = 0; i < 3; i++) {
bn_free(v1[i]);
bn_free(v2[i]);
}
}
}
/**
* Multiplies a prime elliptic curve point by an integer using the COMBS
* method.
*
* @param[out] r - the result.
* @param[in] t - the precomputed table.
* @param[in] k - the integer.
*/
static void ed_mul_combs_endom(ed_t r, const ed_t *t, const bn_t k) {
int i, j, l, w0, w1, n0, n1, p0, p1, s0, s1;
bn_t n, k0, k1, v1[3], v2[3];
ed_t u;
bn_null(n);
bn_null(k0);
bn_null(k1);
ed_null(u);
TRY {
bn_new(n);
bn_new(k0);
bn_new(k1);
ed_new(u);
for (i = 0; i < 3; i++) {
bn_null(v1[i]);
bn_null(v2[i]);
bn_new(v1[i]);
bn_new(v2[i]);
}
ed_curve_get_ord(n);
ed_curve_get_v1(v1);
ed_curve_get_v2(v2);
l = bn_bits(n);
l = ((l % (2 * ED_DEPTH)) ==
0 ? (l / (2 * ED_DEPTH)) : (l / (2 * ED_DEPTH)) + 1);
bn_rec_glv(k0, k1, k, n, (const bn_t *)v1, (const bn_t *)v2);
s0 = bn_sign(k0);
s1 = bn_sign(k1);
bn_abs(k0, k0);
bn_abs(k1, k1);
n0 = bn_bits(k0);
n1 = bn_bits(k1);
p0 = (ED_DEPTH) * l - 1;
ed_set_infty(r);
for (i = l - 1; i >= 0; i--) {
ed_dbl(r, r);
w0 = 0;
w1 = 0;
p1 = p0--;
for (j = ED_DEPTH - 1; j >= 0; j--, p1 -= l) {
w0 = w0 << 1;
w1 = w1 << 1;
if (p1 < n0 && bn_get_bit(k0, p1)) {
w0 = w0 | 1;
}
if (p1 < n1 && bn_get_bit(k1, p1)) {
w1 = w1 | 1;
}
}
if (w0 > 0) {
if (s0 == BN_POS) {
ed_add(r, r, t[w0]);
} else {
ed_sub(r, r, t[w0]);
}
}
if (w1 > 0) {
ed_copy(u, t[w1]);
fp_mul(u->x, u->x, ed_curve_get_beta());
if (s1 == BN_NEG) {
ed_neg(u, u);
}
ed_add(r, r, u);
}
}
ed_norm(r, r);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(n);
bn_free(k0);
bn_free(k1);
ed_free(u);
for (i = 0; i < 3; i++) {
bn_free(v1[i]);
bn_free(v2[i]);
}
}
}
static Boolean
kcl_int_sign(cint_t *ai)
{
return(bn_sign(ai->cint_data));
}
void bn_rand_mod(bn_t a, bn_t b) {
do {
bn_rand(a, bn_sign(b), bn_bits(b));
} while (bn_is_zero(a) || bn_cmp_abs(a, b) != CMP_LT);
}
int cp_rsa_enc(uint8_t *out, int *out_len, uint8_t *in, int in_len, rsa_t pub) {
bn_t m, eb;
int size, pad_len, result = STS_OK;
bn_null(m);
bn_null(eb);
bn_size_bin(&size, pub->n);
if (pub == NULL || in_len <= 0 || in_len > (size - RSA_PAD_LEN)) {
return STS_ERR;
}
TRY {
bn_new(m);
bn_new(eb);
bn_zero(m);
bn_zero(eb);
#if CP_RSAPD == BASIC
if (pad_basic(eb, &pad_len, in_len, size, RSA_ENC) == STS_OK) {
#elif CP_RSAPD == PKCS1
if (pad_pkcs1(eb, &pad_len, in_len, size, RSA_ENC) == STS_OK) {
#elif CP_RSAPD == PKCS2
if (pad_pkcs2(eb, &pad_len, in_len, size, RSA_ENC) == STS_OK) {
#endif
bn_read_bin(m, in, in_len);
bn_add(eb, eb, m);
#if CP_RSAPD == PKCS2
pad_pkcs2(eb, &pad_len, in_len, size, RSA_ENC_FIN);
#endif
bn_mxp(eb, eb, pub->e, pub->n);
if (size <= *out_len) {
*out_len = size;
memset(out, 0, *out_len);
bn_write_bin(out, size, eb);
} else {
result = STS_ERR;
}
} else {
result = STS_ERR;
}
}
CATCH_ANY {
result = STS_ERR;
}
FINALLY {
bn_free(m);
bn_free(eb);
}
return result;
}
#if CP_RSA == BASIC || !defined(STRIP)
int cp_rsa_dec_basic(uint8_t *out, int *out_len, uint8_t *in, int in_len, rsa_t prv) {
bn_t m, eb;
int size, pad_len, result = STS_OK;
bn_size_bin(&size, prv->n);
if (prv == NULL || in_len != size || in_len < RSA_PAD_LEN) {
return STS_ERR;
}
bn_null(m);
bn_null(eb);
TRY {
bn_new(m);
bn_new(eb);
bn_read_bin(eb, in, in_len);
bn_mxp(eb, eb, prv->d, prv->n);
if (bn_cmp(eb, prv->n) != CMP_LT) {
result = STS_ERR;
}
#if CP_RSAPD == BASIC
if (pad_basic(eb, &pad_len, in_len, size, RSA_DEC) == STS_OK) {
#elif CP_RSAPD == PKCS1
if (pad_pkcs1(eb, &pad_len, in_len, size, RSA_DEC) == STS_OK) {
#elif CP_RSAPD == PKCS2
if (pad_pkcs2(eb, &pad_len, in_len, size, RSA_DEC) == STS_OK) {
#endif
size = size - pad_len;
if (size <= *out_len) {
memset(out, 0, size);
bn_write_bin(out, size, eb);
*out_len = size;
} else {
result = STS_ERR;
}
} else {
result = STS_ERR;
}
}
CATCH_ANY {
result = STS_ERR;
}
FINALLY {
bn_free(m);
bn_free(eb);
}
return result;
}
#endif
#if CP_RSA == QUICK || !defined(STRIP)
int cp_rsa_dec_quick(uint8_t *out, int *out_len, uint8_t *in, int in_len, rsa_t prv) {
bn_t m, eb;
int size, pad_len, result = STS_OK;
bn_null(m);
bn_null(eb);
bn_size_bin(&size, prv->n);
if (prv == NULL || in_len != size || in_len < RSA_PAD_LEN) {
return STS_ERR;
}
TRY {
bn_new(m);
bn_new(eb);
bn_read_bin(eb, in, in_len);
bn_copy(m, eb);
/* m1 = c^dP mod p. */
bn_mxp(eb, eb, prv->dp, prv->p);
/* m2 = c^dQ mod q. */
bn_mxp(m, m, prv->dq, prv->q);
/* m1 = m1 - m2 mod p. */
bn_sub(eb, eb, m);
while (bn_sign(eb) == BN_NEG) {
bn_add(eb, eb, prv->p);
}
bn_mod(eb, eb, prv->p);
/* m1 = qInv(m1 - m2) mod p. */
bn_mul(eb, eb, prv->qi);
bn_mod(eb, eb, prv->p);
/* m = m2 + m1 * q. */
bn_mul(eb, eb, prv->q);
bn_add(eb, eb, m);
if (bn_cmp(eb, prv->n) != CMP_LT) {
result = STS_ERR;
}
#if CP_RSAPD == BASIC
if (pad_basic(eb, &pad_len, in_len, size, RSA_DEC) == STS_OK) {
#elif CP_RSAPD == PKCS1
if (pad_pkcs1(eb, &pad_len, in_len, size, RSA_DEC) == STS_OK) {
#elif CP_RSAPD == PKCS2
if (pad_pkcs2(eb, &pad_len, in_len, size, RSA_DEC) == STS_OK) {
#endif
size = size - pad_len;
if (size <= *out_len) {
memset(out, 0, size);
bn_write_bin(out, size, eb);
*out_len = size;
} else {
result = STS_ERR;
}
} else {
result = STS_ERR;
}
}
CATCH_ANY {
result = STS_ERR;
}
FINALLY {
bn_free(m);
bn_free(eb);
}
return result;
}
#endif
#if CP_RSA == BASIC || !defined(STRIP)
int cp_rsa_sig_basic(uint8_t *sig, int *sig_len, uint8_t *msg, int msg_len, int hash, rsa_t prv) {
bn_t m, eb;
int size, pad_len, result = STS_OK;
uint8_t h[MD_LEN];
if (prv == NULL || msg_len < 0) {
return STS_ERR;
}
pad_len = (!hash ? MD_LEN : msg_len);
#if CP_RSAPD == PKCS2
size = bn_bits(prv->n) - 1;
size = (size / 8) + (size % 8 > 0);
if (pad_len > (size - 2)) {
return STS_ERR;
}
#else
bn_size_bin(&size, prv->n);
if (pad_len > (size - RSA_PAD_LEN)) {
return STS_ERR;
}
#endif
bn_null(m);
bn_null(eb);
TRY {
bn_new(m);
bn_new(eb);
bn_zero(m);
bn_zero(eb);
int operation = (!hash ? RSA_SIG : RSA_SIG_HASH);
#if CP_RSAPD == BASIC
if (pad_basic(eb, &pad_len, pad_len, size, operation) == STS_OK) {
#elif CP_RSAPD == PKCS1
if (pad_pkcs1(eb, &pad_len, pad_len, size, operation) == STS_OK) {
#elif CP_RSAPD == PKCS2
if (pad_pkcs2(eb, &pad_len, pad_len, size, operation) == STS_OK) {
#endif
if (!hash) {
md_map(h, msg, msg_len);
bn_read_bin(m, h, MD_LEN);
bn_add(eb, eb, m);
} else {
bn_read_bin(m, msg, msg_len);
bn_add(eb, eb, m);
}
#if CP_RSAPD == PKCS2
pad_pkcs2(eb, &pad_len, bn_bits(prv->n), size, RSA_SIG_FIN);
#endif
bn_mxp(eb, eb, prv->d, prv->n);
bn_size_bin(&size, prv->n);
if (size <= *sig_len) {
memset(sig, 0, size);
bn_write_bin(sig, size, eb);
*sig_len = size;
} else {
result = STS_ERR;
}
} else {
result = STS_ERR;
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(m);
bn_free(eb);
}
return result;
}
#endif
#if CP_RSA == QUICK || !defined(STRIP)
int cp_rsa_sig_quick(uint8_t *sig, int *sig_len, uint8_t *msg, int msg_len, int hash, rsa_t prv) {
bn_t m, eb;
int pad_len, size, result = STS_OK;
uint8_t h[MD_LEN];
if (prv == NULL || msg_len < 0) {
return STS_ERR;
}
pad_len = (!hash ? MD_LEN : msg_len);
#if CP_RSAPD == PKCS2
size = bn_bits(prv->n) - 1;
size = (size / 8) + (size % 8 > 0);
if (pad_len > (size - 2)) {
return STS_ERR;
}
#else
bn_size_bin(&size, prv->n);
if (pad_len > (size - RSA_PAD_LEN)) {
return STS_ERR;
}
#endif
bn_null(m);
bn_null(eb);
TRY {
bn_new(m);
bn_new(eb);
bn_zero(m);
bn_zero(eb);
int operation = (!hash ? RSA_SIG : RSA_SIG_HASH);
#if CP_RSAPD == BASIC
if (pad_basic(eb, &pad_len, pad_len, size, operation) == STS_OK) {
#elif CP_RSAPD == PKCS1
if (pad_pkcs1(eb, &pad_len, pad_len, size, operation) == STS_OK) {
#elif CP_RSAPD == PKCS2
if (pad_pkcs2(eb, &pad_len, pad_len, size, operation) == STS_OK) {
#endif
if (!hash) {
md_map(h, msg, msg_len);
bn_read_bin(m, h, MD_LEN);
bn_add(eb, eb, m);
} else {
bn_read_bin(m, msg, msg_len);
bn_add(eb, eb, m);
}
#if CP_RSAPD == PKCS2
pad_pkcs2(eb, &pad_len, bn_bits(prv->n), size, RSA_SIG_FIN);
#endif
bn_copy(m, eb);
/* m1 = c^dP mod p. */
bn_mxp(eb, eb, prv->dp, prv->p);
/* m2 = c^dQ mod q. */
bn_mxp(m, m, prv->dq, prv->q);
/* m1 = m1 - m2 mod p. */
bn_sub(eb, eb, m);
while (bn_sign(eb) == BN_NEG) {
bn_add(eb, eb, prv->p);
}
bn_mod(eb, eb, prv->p);
/* m1 = qInv(m1 - m2) mod p. */
bn_mul(eb, eb, prv->qi);
bn_mod(eb, eb, prv->p);
/* m = m2 + m1 * q. */
bn_mul(eb, eb, prv->q);
bn_add(eb, eb, m);
bn_mod(eb, eb, prv->n);
bn_size_bin(&size, prv->n);
if (size <= *sig_len) {
memset(sig, 0, size);
bn_write_bin(sig, size, eb);
*sig_len = size;
} else {
result = STS_ERR;
}
} else {
result = STS_ERR;
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(m);
bn_free(eb);
}
return result;
}
#endif
int cp_rsa_ver(uint8_t *sig, int sig_len, uint8_t *msg, int msg_len, int hash, rsa_t pub) {
bn_t m, eb;
int size, pad_len, result;
uint8_t h1[MAX(msg_len, MD_LEN) + 8], h2[MAX(msg_len, MD_LEN)];
/* We suppose that the signature is invalid. */
result = 0;
if (pub == NULL || msg_len < 0) {
return 0;
}
pad_len = (!hash ? MD_LEN : msg_len);
#if CP_RSAPD == PKCS2
size = bn_bits(pub->n) - 1;
if (size % 8 == 0) {
size = size / 8 - 1;
} else {
bn_size_bin(&size, pub->n);
}
if (pad_len > (size - 2)) {
return 0;
}
#else
bn_size_bin(&size, pub->n);
if (pad_len > (size - RSA_PAD_LEN)) {
return 0;
}
#endif
bn_null(m);
bn_null(eb);
TRY {
bn_new(m);
bn_new(eb);
bn_read_bin(eb, sig, sig_len);
bn_mxp(eb, eb, pub->e, pub->n);
int operation = (!hash ? RSA_VER : RSA_VER_HASH);
#if CP_RSAPD == BASIC
if (pad_basic(eb, &pad_len, MD_LEN, size, operation) == STS_OK) {
#elif CP_RSAPD == PKCS1
if (pad_pkcs1(eb, &pad_len, MD_LEN, size, operation) == STS_OK) {
#elif CP_RSAPD == PKCS2
if (pad_pkcs2(eb, &pad_len, bn_bits(pub->n), size, operation) == STS_OK) {
#endif
#if CP_RSAPD == PKCS2
memset(h1, 0, 8);
if (!hash) {
md_map(h1 + 8, msg, msg_len);
md_map(h2, h1, MD_LEN + 8);
memset(h1, 0, MD_LEN);
bn_write_bin(h1, size - pad_len, eb);
/* Everything went ok, so signature status is changed. */
result = util_cmp_const(h1, h2, MD_LEN);
} else {
memcpy(h1 + 8, msg, msg_len);
md_map(h2, h1, MD_LEN + 8);
memset(h1, 0, msg_len);
bn_write_bin(h1, size - pad_len, eb);
/* Everything went ok, so signature status is changed. */
result = util_cmp_const(h1, h2, msg_len);
}
#else
memset(h1, 0, MAX(msg_len, MD_LEN));
bn_write_bin(h1, size - pad_len, eb);
if (!hash) {
md_map(h2, msg, msg_len);
/* Everything went ok, so signature status is changed. */
result = util_cmp_const(h1, h2, MD_LEN);
} else {
/* Everything went ok, so signature status is changed. */
result = util_cmp_const(h1, msg, msg_len);
}
#endif
result = (result == CMP_EQ ? 1 : 0);
} else {
result = 0;
}
}
CATCH_ANY {
result = 0;
}
FINALLY {
bn_free(m);
bn_free(eb);
}
return result;
}
/**
* Computes the final exponentiation of a pairing defined over a Barreto-Naehrig
* curve.
*
* @param[out] c - the result.
* @param[in] a - the extension field element to exponentiate.
*/
static void pp_exp_bn(fp12_t c, fp12_t a) {
fp12_t t0, t1, t2, t3;
int l = MAX_TERMS + 1, b[MAX_TERMS + 1];
bn_t x;
fp12_null(t0);
fp12_null(t1);
fp12_null(t2);
fp12_null(t3);
bn_null(x);
TRY {
fp12_new(t0);
fp12_new(t1);
fp12_new(t2);
fp12_new(t3);
bn_new(x);
/*
* New final exponentiation following Fuentes-Castañeda, Knapp and
* Rodríguez-Henríquez: Fast Hashing to G_2.
*/
fp_param_get_var(x);
fp_param_get_sps(b, &l);
/* First, compute m = f^(p^6 - 1)(p^2 + 1). */
fp12_conv_cyc(c, a);
/* Now compute m^((p^4 - p^2 + 1) / r). */
/* t0 = m^2x. */
fp12_exp_cyc_sps(t0, c, b, l);
fp12_sqr_cyc(t0, t0);
/* t1 = m^6x. */
fp12_sqr_cyc(t1, t0);
fp12_mul(t1, t1, t0);
/* t2 = m^6x^2. */
fp12_exp_cyc_sps(t2, t1, b, l);
/* t3 = m^12x^3. */
fp12_sqr_cyc(t3, t2);
fp12_exp_cyc_sps(t3, t3, b, l);
if (bn_sign(x) == BN_NEG) {
fp12_inv_uni(t0, t0);
fp12_inv_uni(t1, t1);
fp12_inv_uni(t3, t3);
}
/* t3 = a = m^12x^3 * m^6x^2 * m^6x. */
fp12_mul(t3, t3, t2);
fp12_mul(t3, t3, t1);
/* t0 = b = 1/(m^2x) * t3. */
fp12_inv_uni(t0, t0);
fp12_mul(t0, t0, t3);
/* Compute t2 * t3 * m * b^p * a^p^2 * [b * 1/m]^p^3. */
fp12_mul(t2, t2, t3);
fp12_mul(t2, t2, c);
fp12_inv_uni(c, c);
fp12_mul(c, c, t0);
fp12_frb(c, c, 3);
fp12_mul(c, c, t2);
fp12_frb(t0, t0, 1);
fp12_mul(c, c, t0);
fp12_frb(t3, t3, 2);
fp12_mul(c, c, t3);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
fp12_free(t0);
fp12_free(t1);
fp12_free(t2);
fp12_free(t3);
bn_free(x);
}
}
void pp_map_sim_oatep_k12(fp12_t r, ep_t *p, ep2_t *q, int m) {
ep_t _p[m];
ep2_t t[m], _q[m];
bn_t a;
int i, j, len = FP_BITS, s[FP_BITS];
TRY {
bn_null(a);
bn_new(a);
for (i = 0; i < m; i++) {
ep_null(_p[i]);
ep2_null(_q[i]);
ep2_null(t[i]);
ep_new(_p[i]);
ep2_new(_q[i]);
ep2_new(t[i]);
}
j = 0;
for (i = 0; i < m; i++) {
if (!ep_is_infty(p[i]) && !ep2_is_infty(q[i])) {
ep_norm(_p[j], p[i]);
ep2_norm(_q[j++], q[i]);
}
}
fp12_set_dig(r, 1);
fp_param_get_var(a);
bn_mul_dig(a, a, 6);
bn_add_dig(a, a, 2);
fp_param_get_map(s, &len);
if (j > 0) {
switch (ep_param_get()) {
case BN_P158:
case BN_P254:
case BN_P256:
case BN_P638:
/* r = f_{|a|,Q}(P). */
pp_mil_sps_k12(r, t, _q, _p, j, s, len);
if (bn_sign(a) == BN_NEG) {
/* f_{-a,Q}(P) = 1/f_{a,Q}(P). */
fp12_inv_uni(r, r);
}
for (i = 0; i < j; i++) {
if (bn_sign(a) == BN_NEG) {
ep2_neg(t[i], t[i]);
}
pp_fin_k12_oatep(r, t[i], _q[i], _p[i]);
}
pp_exp_k12(r, r);
break;
case B12_P638:
/* r = f_{|a|,Q}(P). */
pp_mil_sps_k12(r, t, _q, _p, j, s, len);
if (bn_sign(a) == BN_NEG) {
fp12_inv_uni(r, r);
}
pp_exp_k12(r, r);
break;
}
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(a);
for (i = 0; i < m; i++) {
ep_free(_p[i]);
ep2_free(_q[i]);
ep2_free(t[i]);
}
}
}
/**
* Multiplies and adds two prime elliptic curve points simultaneously,
* optionally choosing the first point as the generator depending on an optional
* table of precomputed points.
*
* @param[out] r - the result.
* @param[in] p - the first point to multiply.
* @param[in] k - the first integer.
* @param[in] q - the second point to multiply.
* @param[in] m - the second integer.
* @param[in] t - the pointer to the precomputed table.
*/
static void ep_mul_sim_plain(ep_t r, const ep_t p, const bn_t k, const ep_t q,
const bn_t m, const ep_t *t) {
int i, l, l0, l1, n0, n1, w, gen;
int8_t naf0[FP_BITS + 1], naf1[FP_BITS + 1], *_k, *_m;
ep_t t0[1 << (EP_WIDTH - 2)];
ep_t t1[1 << (EP_WIDTH - 2)];
for (i = 0; i < (1 << (EP_WIDTH - 2)); i++) {
ep_null(t0[i]);
ep_null(t1[i]);
}
TRY {
gen = (t == NULL ? 0 : 1);
if (!gen) {
for (i = 0; i < (1 << (EP_WIDTH - 2)); i++) {
ep_new(t0[i]);
}
ep_tab(t0, p, EP_WIDTH);
t = (const ep_t *)t0;
}
/* Prepare the precomputation table. */
for (i = 0; i < (1 << (EP_WIDTH - 2)); i++) {
ep_new(t1[i]);
}
/* Compute the precomputation table. */
ep_tab(t1, q, EP_WIDTH);
/* Compute the w-TNAF representation of k. */
if (gen) {
w = EP_DEPTH;
} else {
w = EP_WIDTH;
}
l0 = l1 = FP_BITS + 1;
bn_rec_naf(naf0, &l0, k, w);
bn_rec_naf(naf1, &l1, m, EP_WIDTH);
l = MAX(l0, l1);
for (i = l0; i < l; i++) {
naf0[i] = 0;
}
for (i = l1; i < l; i++) {
naf1[i] = 0;
}
if (bn_sign(k) == BN_NEG) {
for (i = 0; i < l0; i++) {
naf0[i] = -naf0[i];
}
}
if (bn_sign(m) == BN_NEG) {
for (i = 0; i < l1; i++) {
naf1[i] = -naf1[i];
}
}
_k = naf0 + l - 1;
_m = naf1 + l - 1;
ep_set_infty(r);
for (i = l - 1; i >= 0; i--, _k--, _m--) {
ep_dbl(r, r);
n0 = *_k;
n1 = *_m;
if (n0 > 0) {
ep_add(r, r, t[n0 / 2]);
}
if (n0 < 0) {
ep_sub(r, r, t[-n0 / 2]);
}
if (n1 > 0) {
ep_add(r, r, t1[n1 / 2]);
}
if (n1 < 0) {
ep_sub(r, r, t1[-n1 / 2]);
}
}
/* Convert r to affine coordinates. */
ep_norm(r, r);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
/* Free the precomputation tables. */
if (!gen) {
for (i = 0; i < 1 << (EP_WIDTH - 2); i++) {
ep_free(t0[i]);
}
}
for (i = 0; i < 1 << (EP_WIDTH - 2); i++) {
ep_free(t1[i]);
}
}
}
static void ed_mul_naf_imp(ed_t r, const ed_t p, const bn_t k) {
int l, i, n;
int8_t naf[RLC_FP_BITS + 1];
ed_t t[1 << (ED_WIDTH - 2)];
if (bn_is_zero(k)) {
ed_set_infty(r);
return;
}
TRY {
/* Prepare the precomputation table. */
for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
ed_null(t[i]);
ed_new(t[i]);
}
/* Compute the precomputation table. */
ed_tab(t, p, ED_WIDTH);
/* Compute the w-NAF representation of k. */
l = sizeof(naf);
bn_rec_naf(naf, &l, k, EP_WIDTH);
ed_set_infty(r);
for (i = l - 1; i > 0; i--) {
n = naf[i];
if (n == 0) {
/* This point will be doubled in the previous iteration. */
r->norm = 2;
ed_dbl(r, r);
} else {
ed_dbl(r, r);
if (n > 0) {
ed_add(r, r, t[n / 2]);
} else if (n < 0) {
ed_sub(r, r, t[-n / 2]);
}
}
}
/* Last iteration. */
n = naf[0];
ed_dbl(r, r);
if (n > 0) {
ed_add(r, r, t[n / 2]);
} else if (n < 0) {
ed_sub(r, r, t[-n / 2]);
}
/* Convert r to affine coordinates. */
ed_norm(r, r);
if (bn_sign(k) == RLC_NEG) {
ed_neg(r, r);
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
/* Free the precomputation table. */
for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
ed_free(t[i]);
}
}
}
void pp_map_oatep_k12(fp12_t r, ep_t p, ep2_t q) {
ep_t _p[1];
ep2_t t[1], _q[1];
bn_t a;
int len = FP_BITS, s[FP_BITS];
ep_null(_p[0]);
ep2_null(_q[0]);
ep2_null(t[0]);
bn_null(a);
TRY {
ep_new(_p[0]);
ep2_new(_q[0]);
ep2_new(t[0]);
bn_new(a);
fp_param_get_var(a);
bn_mul_dig(a, a, 6);
bn_add_dig(a, a, 2);
fp_param_get_map(s, &len);
fp12_set_dig(r, 1);
ep_norm(_p[0], p);
ep2_norm(_q[0], q);
if (!ep_is_infty(_p[0]) && !ep2_is_infty(_q[0])) {
switch (ep_param_get()) {
case BN_P158:
case BN_P254:
case BN_P256:
case BN_P638:
/* r = f_{|a|,Q}(P). */
pp_mil_sps_k12(r, t, _q, _p, 1, s, len);
if (bn_sign(a) == BN_NEG) {
/* f_{-a,Q}(P) = 1/f_{a,Q}(P). */
fp12_inv_uni(r, r);
ep2_neg(t[0], t[0]);
}
pp_fin_k12_oatep(r, t[0], _q[0], _p[0]);
pp_exp_k12(r, r);
break;
case B12_P638:
/* r = f_{|a|,Q}(P). */
pp_mil_sps_k12(r, t, _q, _p, 1, s, len);
if (bn_sign(a) == BN_NEG) {
fp12_inv_uni(r, r);
ep2_neg(t[0], t[0]);
}
pp_exp_k12(r, r);
break;
}
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
ep_free(_p[0]);
ep2_free(_q[0]);
ep2_free(t[0]);
bn_free(a);
}
}
void ed_mul_slide(ed_t r, const ed_t p, const bn_t k) {
ed_t t[1 << (EP_WIDTH - 1)], q;
int i, j, l;
uint8_t win[RLC_FP_BITS + 1];
ed_null(q);
if (bn_is_zero(k) || ed_is_infty(p)) {
ed_set_infty(r);
return;
}
TRY {
for (i = 0; i < (1 << (EP_WIDTH - 1)); i ++) {
ed_null(t[i]);
ed_new(t[i]);
}
ed_new(q);
ed_copy(t[0], p);
ed_dbl(q, p);
#if defined(EP_MIXED)
ed_norm(q, q);
#endif
/* Create table. */
for (i = 1; i < (1 << (EP_WIDTH - 1)); i++) {
ed_add(t[i], t[i - 1], q);
}
#if defined(EP_MIXED)
ed_norm_sim(t + 1, (const ed_t *)t + 1, (1 << (EP_WIDTH - 1)) - 1);
#endif
ed_set_infty(q);
l = RLC_FP_BITS + 1;
bn_rec_slw(win, &l, k, EP_WIDTH);
for (i = 0; i < l; i++) {
if (win[i] == 0) {
ed_dbl(q, q);
} else {
for (j = 0; j < util_bits_dig(win[i]); j++) {
ed_dbl(q, q);
}
ed_add(q, q, t[win[i] >> 1]);
}
}
ed_norm(r, q);
if (bn_sign(k) == RLC_NEG) {
ed_neg(r, r);
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
for (i = 0; i < (1 << (EP_WIDTH - 1)); i++) {
ed_free(t[i]);
}
ed_free(q);
}
}
void fp_exp_slide(fp_t c, const fp_t a, const bn_t b) {
fp_t t[1 << (FP_WIDTH - 1)], r;
int i, j, l;
uint8_t win[FP_BITS + 1];
fp_null(r);
if (bn_is_zero(b)) {
fp_set_dig(c, 1);
return;
}
/* Initialize table. */
for (i = 0; i < (1 << (FP_WIDTH - 1)); i++) {
fp_null(t[i]);
}
TRY {
for (i = 0; i < (1 << (FP_WIDTH - 1)); i ++) {
fp_new(t[i]);
}
fp_new(r);
fp_copy(t[0], a);
fp_sqr(r, a);
/* Create table. */
for (i = 1; i < 1 << (FP_WIDTH - 1); i++) {
fp_mul(t[i], t[i - 1], r);
}
fp_set_dig(r, 1);
l = FP_BITS + 1;
bn_rec_slw(win, &l, b, FP_WIDTH);
for (i = 0; i < l; i++) {
if (win[i] == 0) {
fp_sqr(r, r);
} else {
for (j = 0; j < util_bits_dig(win[i]); j++) {
fp_sqr(r, r);
}
fp_mul(r, r, t[win[i] >> 1]);
}
}
if (bn_sign(b) == BN_NEG) {
fp_inv(c, r);
} else {
fp_copy(c, r);
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
for (i = 0; i < (1 << (FP_WIDTH - 1)); i++) {
fp_free(t[i]);
}
fp_free(r);
}
}
void fp_param_get_sps(int *s, int *len) {
bn_t a;
bn_null(a);
if (*len < MAX_TERMS) {
THROW(ERR_NO_BUFFER);
}
TRY {
bn_new(a);
*len = 0;
switch (fp_param_get()) {
case BN_158:
case BN_254:
case BN_256:
fp_param_get_var(a);
if (bn_sign(a) == BN_NEG) {
bn_neg(a, a);
}
*len = bn_ham(a);
for (int i = 0, j = 0; j < bn_bits(a); j++) {
if (bn_test_bit(a, j)) {
s[i++] = j;
}
}
break;
case B24_477:
s[0] = 7;
s[1] = -31;
s[2] = -45;
s[3] = 48;
*len = 4;
break;
case KSS_508:
s[0] = -12;
s[1] = -46;
s[2] = 51;
s[3] = 64;
*len = 4;
break;
case BN_638:
s[0] = 0;
s[1] = -68;
s[2] = -128;
s[3] = 158;
*len = 4;
break;
case B12_638:
s[0] = -5;
s[1] = -93;
s[2] = -105;
s[3] = 107;
*len = 4;
break;
case SS_1536:
s[0] = 0;
s[1] = 41;
s[2] = 255;
*len = 3;
break;
default:
THROW(ERR_NO_VALID);
break;
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(a);
}
}
int bn_is_prime_solov(const bn_t a) {
bn_t t0, t1, t2;
int i, result;
bn_null(t0);
bn_null(t1);
bn_null(t2);
result = 1;
TRY {
bn_new(t0);
bn_new(t1);
bn_new(t2);
for (i = 0; i < 100; i++) {
/* Generate t0, 2 <= t0, <= a - 2. */
do {
bn_rand(t0, BN_POS, bn_bits(a));
bn_mod(t0, t0, a);
} while (bn_cmp_dig(t0, 2) == CMP_LT);
/* t2 = a - 1. */
bn_copy(t2, a);
bn_sub_dig(t2, t2, 1);
/* t1 = (a - 1)/2. */
bn_rsh(t1, t2, 1);
/* t1 = t0^(a - 1)/2 mod a. */
#if BN_MOD != PMERS
bn_mxp(t1, t0, t1, a);
#else
bn_exp(t1, t0, t1, a);
#endif
/* If t1 != 1 and t1 != n - 1 return 0 */
if (bn_cmp_dig(t1, 1) != CMP_EQ && bn_cmp(t1, t2) != CMP_EQ) {
result = 0;
break;
}
/* t2 = (t0|a). */
bn_smb_jac(t2, t0, a);
if (bn_sign(t2) == BN_NEG) {
bn_add(t2, t2, a);
}
/* If t1 != t2 (mod a) return 0. */
bn_mod(t1, t1, a);
bn_mod(t2, t2, a);
if (bn_cmp(t1, t2) != CMP_EQ) {
result = 0;
break;
}
}
}
CATCH_ANY {
result = 0;
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(t0);
bn_free(t1);
bn_free(t2);
}
return result;
}
void ep_mul_sim_trick(ep_t r, const ep_t p, const bn_t k, const ep_t q,
const bn_t m) {
ep_t t0[1 << (EP_WIDTH / 2)], t1[1 << (EP_WIDTH / 2)], t[1 << EP_WIDTH];
bn_t n;
int l0, l1, w = EP_WIDTH / 2;
uint8_t w0[CEIL(FP_BITS + 1, w)], w1[CEIL(FP_BITS + 1, w)];
bn_null(n);
if (bn_is_zero(k) || ep_is_infty(p)) {
ep_mul(r, q, m);
return;
}
if (bn_is_zero(m) || ep_is_infty(q)) {
ep_mul(r, p, k);
return;
}
TRY {
bn_new(n);
ep_curve_get_ord(n);
for (int i = 0; i < (1 << w); i++) {
ep_null(t0[i]);
ep_null(t1[i]);
ep_new(t0[i]);
ep_new(t1[i]);
}
for (int i = 0; i < (1 << EP_WIDTH); i++) {
ep_null(t[i]);
ep_new(t[i]);
}
ep_set_infty(t0[0]);
ep_copy(t0[1], p);
if (bn_sign(k) == BN_NEG) {
ep_neg(t0[1], t0[1]);
}
for (int i = 2; i < (1 << w); i++) {
ep_add(t0[i], t0[i - 1], t0[1]);
}
ep_set_infty(t1[0]);
ep_copy(t1[1], q);
if (bn_sign(m) == BN_NEG) {
ep_neg(t1[1], t1[1]);
}
for (int i = 1; i < (1 << w); i++) {
ep_add(t1[i], t1[i - 1], t1[1]);
}
for (int i = 0; i < (1 << w); i++) {
for (int j = 0; j < (1 << w); j++) {
ep_add(t[(i << w) + j], t0[i], t1[j]);
}
}
#if defined(EP_MIXED)
ep_norm_sim(t + 1, (const ep_t *)t + 1, (1 << (EP_WIDTH)) - 1);
#endif
l0 = l1 = CEIL(FP_BITS, w);
bn_rec_win(w0, &l0, k, w);
bn_rec_win(w1, &l1, m, w);
for (int i = l0; i < l1; i++) {
w0[i] = 0;
}
for (int i = l1; i < l0; i++) {
w1[i] = 0;
}
ep_set_infty(r);
for (int i = MAX(l0, l1) - 1; i >= 0; i--) {
for (int j = 0; j < w; j++) {
ep_dbl(r, r);
}
ep_add(r, r, t[(w0[i] << w) + w1[i]]);
}
ep_norm(r, r);
} CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(n);
for (int i = 0; i < (1 << w); i++) {
ep_free(t0[i]);
ep_free(t1[i]);
}
for (int i = 0; i < (1 << EP_WIDTH); i++) {
ep_free(t[i]);
}
}
}
int cp_rsa_gen_quick(rsa_t pub, rsa_t prv, int bits) {
bn_t t, r;
int result = STS_OK;
if (pub == NULL || prv == NULL || bits == 0) {
return STS_ERR;
}
bn_null(t);
bn_null(r);
TRY {
bn_new(t);
bn_new(r);
/* Generate different primes p and q. */
do {
bn_gen_prime(prv->p, bits / 2);
bn_gen_prime(prv->q, bits / 2);
} while (bn_cmp(prv->p, prv->q) == CMP_EQ);
/* Swap p and q so that p is smaller. */
if (bn_cmp(prv->p, prv->q) == CMP_LT) {
bn_copy(t, prv->p);
bn_copy(prv->p, prv->q);
bn_copy(prv->q, t);
}
/* n = pq. */
bn_mul(pub->n, prv->p, prv->q);
bn_copy(prv->n, pub->n);
bn_sub_dig(prv->p, prv->p, 1);
bn_sub_dig(prv->q, prv->q, 1);
/* phi(n) = (p - 1)(q - 1). */
bn_mul(t, prv->p, prv->q);
bn_set_2b(pub->e, 16);
bn_add_dig(pub->e, pub->e, 1);
/* d = e^(-1) mod phi(n). */
bn_gcd_ext(r, prv->d, NULL, pub->e, t);
if (bn_sign(prv->d) == BN_NEG) {
bn_add(prv->d, prv->d, t);
}
if (bn_cmp_dig(r, 1) == CMP_EQ) {
/* dP = d mod (p - 1). */
bn_mod(prv->dp, prv->d, prv->p);
/* dQ = d mod (q - 1). */
bn_mod(prv->dq, prv->d, prv->q);
bn_add_dig(prv->p, prv->p, 1);
bn_add_dig(prv->q, prv->q, 1);
/* qInv = q^(-1) mod p. */
bn_gcd_ext(r, prv->qi, NULL, prv->q, prv->p);
if (bn_sign(prv->qi) == BN_NEG) {
bn_add(prv->qi, prv->qi, prv->p);
}
result = STS_OK;
}
}
CATCH_ANY {
result = STS_ERR;
}
FINALLY {
bn_free(t);
bn_free(r);
}
return result;
}
void ep_mul_sim_joint(ep_t r, const ep_t p, const bn_t k, const ep_t q,
const bn_t m) {
ep_t t[5];
int i, u_i, len, offset;
int8_t jsf[2 * (FP_BITS + 1)];
if (bn_is_zero(k) || ep_is_infty(p)) {
ep_mul(r, q, m);
return;
}
if (bn_is_zero(m) || ep_is_infty(q)) {
ep_mul(r, p, k);
return;
}
TRY {
for (i = 0; i < 5; i++) {
ep_null(t[i]);
ep_new(t[i]);
}
ep_set_infty(t[0]);
ep_copy(t[1], q);
if (bn_sign(m) == BN_NEG) {
ep_neg(t[1], t[1]);
}
ep_copy(t[2], p);
if (bn_sign(k) == BN_NEG) {
ep_neg(t[2], t[2]);
}
ep_add(t[3], t[2], t[1]);
ep_sub(t[4], t[2], t[1]);
#if defined(EP_MIXED)
ep_norm_sim(t + 3, (const ep_t *)t + 3, 2);
#endif
len = 2 * (FP_BITS + 1);
bn_rec_jsf(jsf, &len, k, m);
ep_set_infty(r);
offset = MAX(bn_bits(k), bn_bits(m)) + 1;
for (i = len - 1; i >= 0; i--) {
ep_dbl(r, r);
if (jsf[i] != 0 && jsf[i] == -jsf[i + offset]) {
u_i = jsf[i] * 2 + jsf[i + offset];
if (u_i < 0) {
ep_sub(r, r, t[4]);
} else {
ep_add(r, r, t[4]);
}
} else {
u_i = jsf[i] * 2 + jsf[i + offset];
if (u_i < 0) {
ep_sub(r, r, t[-u_i]);
} else {
ep_add(r, r, t[u_i]);
}
}
}
ep_norm(r, r);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
for (i = 0; i < 5; i++) {
ep_free(t[i]);
}
}
}
/**
* Divides two multiple precision integers, computing the quotient and the
* remainder.
*
* @param[out] c - the quotient.
* @param[out] d - the remainder.
* @param[in] a - the dividend.
* @param[in] b - the the divisor.
*/
static void bn_div_imp(bn_t c, bn_t d, const bn_t a, const bn_t b) {
bn_t q, x, y, r;
int sign;
bn_null(q);
bn_null(x);
bn_null(y);
bn_null(r);
/* If a < b, we're done. */
if (bn_cmp_abs(a, b) == CMP_LT) {
if (bn_sign(a) == BN_POS) {
if (c != NULL) {
bn_zero(c);
}
if (d != NULL) {
bn_copy(d, a);
}
} else {
if (c != NULL) {
bn_set_dig(c, 1);
if (bn_sign(b) == BN_POS) {
bn_neg(c, c);
}
}
if (d != NULL) {
if (bn_sign(b) == BN_POS) {
bn_add(d, a, b);
} else {
bn_sub(d, a, b);
}
}
}
return;
}
TRY {
bn_new(x);
bn_new(y);
bn_new_size(q, a->used + 1);
bn_new(r);
bn_zero(q);
bn_zero(r);
bn_abs(x, a);
bn_abs(y, b);
/* Find the sign. */
sign = (a->sign == b->sign ? BN_POS : BN_NEG);
bn_divn_low(q->dp, r->dp, x->dp, a->used, y->dp, b->used);
/* We have the quotient in q and the remainder in r. */
if (c != NULL) {
q->used = a->used - b->used + 1;
q->sign = sign;
bn_trim(q);
if (bn_sign(a) == BN_NEG) {
bn_sub_dig(c, q, 1);
} else {
bn_copy(c, q);
}
}
if (d != NULL) {
r->used = b->used;
r->sign = a->sign;
bn_trim(r);
if (bn_sign(a) == BN_NEG) {
bn_add(d, r, b);
} else {
bn_copy(d, r);
}
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(r);
bn_free(q);
bn_free(x);
bn_free(y);
}
}
/**
* Computes the final exponentiation of a pairing defined over a
* Barreto-Lynn-Scott curve.
*
* @param[out] c - the result.
* @param[in] a - the extension field element to exponentiate.
*/
static void pp_exp_b12(fp12_t c, fp12_t a) {
fp12_t t[10];
bn_t x;
int l = MAX_TERMS + 1, b[MAX_TERMS + 1];
bn_null(x);
TRY {
for (int i = 0; i < 10; i++) {
fp12_null(t[i]);
fp12_new(t[i]);
}
bn_new(x);
fp_param_get_var(x);
fp_param_get_sps(b, &l);
/* First, compute m^(p^6 - 1)(p^2 + 1). */
fp12_conv_cyc(c, a);
/* v0 = f^-1. */
fp12_inv_uni(t[0], c);
/* v1 = f^-2. */
fp12_sqr_cyc(t[1], t[0]);
/* v2 = f^x. */
fp12_exp_cyc_sps(t[2], c, b, l);
if (bn_sign(x) == BN_NEG) {
fp12_inv_uni(t[2], t[2]);
}
/* v3 = f^2x. */
fp12_sqr_cyc(t[3], t[2]);
/* v4 = f^(x - 2). */
fp12_mul(t[4], t[2], t[1]);
/* v5 = f^(x^2 - 2x). */
fp12_exp_cyc_sps(t[5], t[4], b, l);
if (bn_sign(x) == BN_NEG) {
fp12_inv_uni(t[5], t[5]);
}
/* v6 = f^(x^3 - 2x^2). */
fp12_exp_cyc_sps(t[6], t[5], b, l);
if (bn_sign(x) == BN_NEG) {
fp12_inv_uni(t[6], t[6]);
}
/* v7 = f^(x^4 - 2x^3 + 2x). */
fp12_exp_cyc_sps(t[7], t[6], b, l);
if (bn_sign(x) == BN_NEG) {
fp12_inv_uni(t[7], t[7]);
}
fp12_mul(t[7], t[7], t[3]);
/* v8 = f^(x^5 - 2x^4 + 2x^2). */
fp12_exp_cyc_sps(t[8], t[7], b, l);
if (bn_sign(x) == BN_NEG) {
fp12_inv_uni(t[8], t[8]);
}
/* v7 = f^(x^4 - 2x^3 + 2x - 1)^p. */
fp12_mul(t[7], t[7], t[0]);
fp12_frb(t[7], t[7], 1);
/* v6 = f^(x^3 - 2x^2 + x)^p^2. */
fp12_mul(t[6], t[6], t[2]);
fp12_frb(t[6], t[6], 2);
/* v5 = f^(x^2 - 2x + 1)^p^3. */
fp12_mul(t[5], t[5], c);
fp12_frb(t[5], t[5], 1);
fp12_frb(t[5], t[5], 2);
/* v4 = f^(2 - x). */
fp12_inv_uni(t[4], t[4]);
/* Now compute f * v4 * v5 * v6 * v7 * v8. */
fp12_mul(c, c, t[4]);
fp12_mul(c, c, t[5]);
fp12_mul(c, c, t[6]);
fp12_mul(c, c, t[7]);
fp12_mul(c, c, t[8]);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
for (int i = 0; i < 9; i++) {
fp12_free(t[i]);
}
bn_free(x);
}
}
