void fp2_norm_low(fp2_t c, fp2_t a) {
fp2_t t;
bn_t b;
fp2_null(t);
bn_null(b);
TRY {
fp2_new(t);
bn_new(b);
#if FP_PRIME == 158
fp_dbl(t[0], a[0]);
fp_dbl(t[0], t[0]);
fp_sub(t[0], t[0], a[1]);
fp_dbl(t[1], a[1]);
fp_dbl(t[1], t[1]);
fp_add(c[1], a[0], t[1]);
fp_copy(c[0], t[0]);
#elif defined(FP_QNRES)
/* If p = 3 mod 8, (1 + i) is a QNR/CNR. */
fp_neg(t[0], a[1]);
fp_add(c[1], a[0], a[1]);
fp_add(c[0], t[0], a[0]);
#else
switch (fp_prime_get_mod8()) {
case 3:
/* If p = 3 mod 8, (1 + u) is a QNR/CNR. */
fp_neg(t[0], a[1]);
fp_add(c[1], a[0], a[1]);
fp_add(c[0], t[0], a[0]);
break;
case 5:
/* If p = 5 mod 8, (u) is a QNR/CNR. */
fp2_mul_art(c, a);
break;
case 7:
/* If p = 7 mod 8, we choose (2^(lg_4(b-1)) + u) as QNR/CNR. */
fp2_mul_art(t, a);
fp2_dbl(c, a);
fp_prime_back(b, ep_curve_get_b());
for (int i = 1; i < bn_bits(b) / 2; i++) {
fp2_dbl(c, c);
}
fp2_add(c, c, t);
break;
default:
THROW(ERR_NO_VALID);
break;
}
#endif
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
fp2_free(t);
bn_free(b);
}
}
// x = e (copies for ZR, maps x-coordinate for G1, and not defined for G2 or GT)
status_t element_to_int(integer_t x, element_t e)
{
LEAVE_IF(x == NULL || e->isInitialized != TRUE, "uninitialized argument.");
if(e->type == ZR) {
bn_copy(x, e->bn);
}
else if(e->type == G1) {
fp_prime_back(x, e->g1->x);
}
else {
return ELEMENT_INVALID_TYPES;
}
return ELEMENT_OK;
}
void fp_write_bin(unsigned char *str, int len, fp_t a) {
bn_t t;
bn_null(t);
TRY {
bn_new(t);
fp_prime_back(t, a);
bn_write_bin(str, len, t);
} CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(t);
}
}
void fp_write_str(char *str, int len, const fp_t a, int radix) {
bn_t t;
bn_null(t);
TRY {
bn_new(t);
fp_prime_back(t, a);
bn_write_str(str, len, t, radix);
} CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(t);
}
}
int fp_size_str(const fp_t a, int radix) {
bn_t t;
int digits = 0;
bn_null(t);
TRY {
bn_new(t);
fp_prime_back(t, a);
digits = bn_size_str(t, radix);
} CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(t);
}
return digits;
}
void fp_write_bin(uint8_t *bin, int len, const fp_t a) {
bn_t t;
bn_null(t);
if (len != RLC_FP_BYTES) {
THROW(ERR_NO_BUFFER);
}
TRY {
bn_new(t);
fp_prime_back(t, a);
bn_write_bin(bin, len, t);
} CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(t);
}
}
void fp_print(const fp_t a) {
int i;
bn_t t;
bn_null(t);
TRY {
bn_new(t);
#if FP_RDC == MONTY
if (a != fp_prime_get()) {
fp_prime_back(t, a);
} else {
bn_read_raw(t, a, RLC_FP_DIGS);
}
#else
bn_read_raw(t, a, RLC_FP_DIGS);
#endif
for (i = RLC_FP_DIGS - 1; i > 0; i--) {
if (i >= t->used) {
util_print_dig(0, 1);
} else {
util_print_dig(t->dp[i], 1);
}
util_print(" ");
}
util_print_dig(t->dp[0], 1);
util_print("\n");
} CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
bn_free(t);
}
}
void fp2_nord_low(dv2_t c, dv2_t a) {
dv2_t t;
bn_t b;
dv2_null(t);
bn_null(b);
TRY {
dv2_new(t);
bn_new(b);
#if FP_PRIME == 158
fp_addc_low(t[0], a[0], a[0]);
fp_addc_low(t[0], t[0], t[0]);
fp_subc_low(t[0], t[0], a[1]);
fp_addc_low(t[1], a[1], a[1]);
fp_addc_low(t[1], t[1], t[1]);
fp_addc_low(c[1], a[0], t[1]);
dv_copy(c[0], t[0], 2 * FP_DIGS);
#elif defined(FP_QNRES)
/* If p = 3 mod 8, (1 + i) is a QNR/CNR. */
/* (a_0 + a_1 * i) * (1 + i) = (a_0 - a_1) + (a_0 + a_1) * u. */
dv_copy(t[0], a[1], 2 * FP_DIGS);
fp_addc_low(c[1], a[0], a[1]);
fp_subc_low(c[0], a[0], t[0]);
#else
switch (fp_prime_get_mod8()) {
case 3:
/* If p = 3 mod 8, (1 + u) is a QNR, u^2 = -1. */
/* (a_0 + a_1 * u) * (1 + u) = (a_0 - a_1) + (a_0 + a_1) * u. */
dv_copy(t[0], a[1], 2 * FP_DIGS);
fp_addc_low(c[1], a[0], a[1]);
fp_subc_low(c[0], a[0], t[0]);
break;
case 5:
/* If p = 5 mod 8, (u) is a QNR. */
dv_copy(t[0], a[0], 2 * FP_DIGS);
dv_zero(t[1], FP_DIGS);
dv_copy(t[1] + FP_DIGS, fp_prime_get(), FP_DIGS);
fp_subc_low(c[0], t[1], a[1]);
for (int i = -1; i > fp_prime_get_qnr(); i--) {
fp_subc_low(c[0], c[0], a[1]);
}
dv_copy(c[1], t[0], 2 * FP_DIGS);
break;
case 7:
/* If p = 7 mod 8, (2^lg_4(b-1) + u) is a QNR/CNR. */
/* (a_0 + a_1 * u)(2^lg_4(b-1) + u) =
* (2^lg_4(b-1)a_0 - a_1) + (a_0 + 2^lg_4(b-1)a_1 * u. */
fp2_addc_low(t, a, a);
fp_prime_back(b, ep_curve_get_b());
for (int i = 1; i < bn_bits(b) / 2; i++) {
fp2_addc_low(t, t, t);
}
fp_subc_low(c[0], t[0], a[1]);
fp_addc_low(c[1], t[1], a[0]);
break;
default:
THROW(ERR_NO_VALID);
break;
}
#endif
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
dv2_free(t);
bn_free(b);
}
}
