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Simplify code.
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@dfaranha
dfaranha committed Aug 12, 2024
1 parent 0cef413 commit 8b7786f
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Showing 2 changed files with 98 additions and 100 deletions.
18 changes: 7 additions & 11 deletions src/epx/relic_ep2_mul.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,19 +44,19 @@ static void ep2_mul_gls_imp(ep2_t r, const ep2_t p, const bn_t k) {
size_t l, _l[4];
bn_t n, _k[4], u;
int8_t naf[4][RLC_FP_BITS + 1];
ep2_t q[4], t[4][1 << (RLC_WIDTH - 2)];
ep2_t q, t[4][1 << (RLC_WIDTH - 2)];

bn_null(n);
bn_null(u);
ep2_null(q);

RLC_TRY {
bn_new(n);
bn_new(u);
ep2_new(q);
for (size_t i = 0; i < 4; i++) {
bn_null(_k[i]);
ep2_null(q[i]);
bn_new(_k[i]);
ep2_new(q[i]);
for (size_t j = 0; j < (1 << (RLC_WIDTH - 2)); j++) {
ep2_null(t[i][j]);
ep2_new(t[i][j]);
Expand All @@ -68,21 +68,17 @@ static void ep2_mul_gls_imp(ep2_t r, const ep2_t p, const bn_t k) {
bn_mod(_k[0], k, n);
bn_rec_frb(_k, 4, _k[0], u, n, ep_curve_is_pairf() == EP_BN);

ep2_norm(q[0], p);
ep2_frb(q[1], q[0], 1);
ep2_frb(q[2], q[1], 1);
ep2_frb(q[3], q[2], 1);

l = 0;
for (size_t i = 0; i < 4; i++) {
_l[i] = RLC_FP_BITS + 1;
bn_rec_naf(naf[i], &_l[i], _k[i], RLC_WIDTH);
l = RLC_MAX(l, _l[i]);
if (i == 0) {
ep2_norm(q, p);
if (bn_sign(_k[0]) == RLC_NEG) {
ep2_neg(q[0], q[0]);
ep2_neg(q, q);
}
ep2_tab(t[0], q[0], RLC_WIDTH);
ep2_tab(t[0], q, RLC_WIDTH);
} else {
for (size_t j = 0; j < (1 << (RLC_WIDTH - 2)); j++) {
ep2_frb(t[i][j], t[i - 1][j], 1);
Expand Down Expand Up @@ -116,9 +112,9 @@ static void ep2_mul_gls_imp(ep2_t r, const ep2_t p, const bn_t k) {
RLC_FINALLY {
bn_free(n);
bn_free(u);
ep2_free(q);
for (size_t i = 0; i < 4; i++) {
bn_free(_k[i]);
ep2_free(q[i]);
for (size_t j = 0; j < (1 << (RLC_WIDTH - 2)); j++) {
ep2_free(t[i][j]);
}
Expand Down
180 changes: 91 additions & 89 deletions src/pc/relic_pc_exp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -114,21 +114,20 @@ static void gt_psi(gt_t c, const gt_t a) {
* @param[in] b - the exponent.
* @param[in] f - the maximum Frobenius power.
*/
void gt_exp_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
int8_t c0, n0, *reg = RLC_ALLOCA(int8_t, f * (RLC_FP_BITS + 1));
int8_t *e = RLC_ALLOCA(int8_t, f), *s = RLC_ALLOCA(int8_t, f);
gt_t q, w, *t = RLC_ALLOCA(gt_t, f * RLC_GT_TABLE);
void gt_exp_gls_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
int8_t *naf = RLC_ALLOCA(int8_t, f * (RLC_FP_BITS + 1));
int8_t n0, *s = RLC_ALLOCA(int8_t, f);
gt_t q, *t = RLC_ALLOCA(gt_t, f * RLC_GT_TABLE);
bn_t n, u, *_b = RLC_ALLOCA(bn_t, f);
size_t l, len, *_l = RLC_ALLOCA(size_t, f);
size_t l, *_l = RLC_ALLOCA(size_t, f);

if (reg == NULL || e == NULL || t == NULL || _b == NULL || _l == NULL) {
if (naf == NULL || t == NULL || _b == NULL || _l == NULL) {
RLC_THROW(ERR_NO_MEMORY);
return;
}

if (bn_is_zero(b)) {
RLC_FREE(reg);
RLC_FREE(e);
RLC_FREE(naf);
RLC_FREE(s);
RLC_FREE(t);
RLC_FREE(_b);
Expand All @@ -139,13 +138,11 @@ void gt_exp_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
bn_null(n);
bn_null(u);
gt_null(q);
gt_null(w);

RLC_TRY {
bn_new(n);
bn_new(u);
gt_new(q);
gt_new(w);
for (size_t i = 0; i < f; i++) {
bn_null(_b[i]);
bn_new(_b[i]);
Expand All @@ -171,65 +168,55 @@ void gt_exp_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
bn_rec_frb(_b, f, _b[0], u, n, ep_curve_is_pairf() == EP_BN);

l = 0;
len = bn_bits(u) + (ep_curve_is_pairf() == EP_BN);
gt_copy(t[0], a);
for (size_t i = 0; i < f; i++) {
s[i] = bn_sign(_b[i]);
bn_abs(_b[i], _b[i]);
e[i] = bn_is_even(_b[i]);
_b[i]->dp[0] |= e[i];

_l[i] = RLC_FP_BITS + 1;
bn_rec_reg(reg + i * (RLC_FP_BITS + 1), &_l[i], _b[i], len, RLC_WIDTH);
bn_rec_naf(naf + i * (RLC_FP_BITS + 1), &_l[i], _b[i], RLC_WIDTH);
l = RLC_MAX(l, _l[i]);
/* Apply Frobenius before flipping sign to build table. */
if (i > 0) {
gt_psi(t[i * RLC_GT_TABLE], t[(i - 1) * RLC_GT_TABLE]);
}
}

for (size_t i = 0; i < f; i++) {
gt_inv(q, t[i * RLC_GT_TABLE]);
gt_copy_sec(q, t[i * RLC_GT_TABLE], s[i] == RLC_POS);
if (RLC_WIDTH > 2) {
gt_sqr(t[i * RLC_GT_TABLE], q);
gt_mul(t[i * RLC_GT_TABLE + 1], t[i * RLC_GT_TABLE], q);
for (size_t j = 2; j < RLC_GT_TABLE; j++) {
gt_mul(t[i * RLC_GT_TABLE + j], t[i * RLC_GT_TABLE + j - 1],
t[i * (RLC_GT_TABLE)]);
gt_copy(q, a);
if (s[0] == RLC_NEG) {
gt_inv(q, q);
}
if (RLC_WIDTH > 2) {
gt_sqr(t[0], q);
gt_mul(t[1], t[0], q);
for (size_t j = 2; j < RLC_GT_TABLE; j++) {
gt_mul(t[j], t[j - 1], t[0]);
}
}
gt_copy(t[0], q);
for (size_t i = 1; i < f; i++) {
for (size_t j = 0; j < RLC_GT_TABLE; j++) {
gt_frb(t[i * RLC_GT_TABLE + j],
t[(i - 1) * RLC_GT_TABLE + j], 1);
if (s[i] != s[i - 1]) {
gt_inv(t[i * RLC_GT_TABLE + j], t[i * RLC_GT_TABLE + j]);
}
}
gt_copy(t[i * RLC_GT_TABLE], q);
}

gt_set_unity(c);
for (int j = l - 1; j >= 0; j--) {
for (size_t i = 0; i < RLC_WIDTH - 1; i++) {
gt_sqr(c, c);
}
gt_sqr(c, c);

for (size_t i = 0; i < f; i++) {
n0 = reg[i * (RLC_FP_BITS + 1) + j];
c0 = (n0 >> 7);
n0 = ((n0 ^ c0) - c0) >> 1;

for (size_t m = 0; m < RLC_GT_TABLE; m++) {
gt_copy_sec(w, t[i * RLC_GT_TABLE + m], m == n0);
n0 = naf[i * (RLC_FP_BITS + 1) + j];
if (n0 > 0) {
gt_mul(c, c, t[i * RLC_GT_TABLE + n0 / 2]);
}
if (n0 < 0) {
gt_inv(q, t[i * RLC_GT_TABLE - n0 / 2]);
gt_mul(c, c, q);
}

gt_inv(q, w);
gt_copy_sec(q, w, c0 == 0);
gt_mul(c, c, q);

}
}

for (size_t i = 0; i < f; i++) {
/* Tables are built with points already negated, so no need here. */
gt_inv(q, t[i * RLC_GT_TABLE]);
gt_mul(q, c, q);
gt_copy_sec(c, q, e[i]);
}
}
RLC_CATCH_ANY {
RLC_THROW(ERR_CAUGHT);
Expand All @@ -238,27 +225,20 @@ void gt_exp_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
bn_free(n);
bn_free(u);
gt_free(q);
gt_free(w);
for (size_t i = 0; i < f; i++) {
bn_free(_b[i]);
for (size_t j = 0; j < RLC_GT_TABLE; j++) {
gt_free(t[i * RLC_GT_TABLE + j]);
}
}
RLC_FREE(reg);
RLC_FREE(e);
RLC_FREE(naf);
RLC_FREE(s);
RLC_FREE(t);
RLC_FREE(_b);
RLC_FREE(_l);
}
}

/**
* Size of a precomputation table using the double-table comb method.
*/
#define RLC_GT_TABLE (1 << (RLC_WIDTH - 2))

/**
* Exponentiates an element from G_T in constant time.
*
Expand All @@ -267,20 +247,21 @@ void gt_exp_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
* @param[in] b - the exponent.
* @param[in] f - the maximum Frobenius power.
*/
void gt_exp_gls_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
int8_t *naf = RLC_ALLOCA(int8_t, f * (RLC_FP_BITS + 1));
int8_t n0, *s = RLC_ALLOCA(int8_t, f);
gt_t q, *t = RLC_ALLOCA(gt_t, f * RLC_GT_TABLE);
void gt_exp_reg_gls(gt_t c, const gt_t a, const bn_t b, size_t f) {
int8_t c0, n0, *reg = RLC_ALLOCA(int8_t, f * (RLC_FP_BITS + 1));
int8_t *e = RLC_ALLOCA(int8_t, f), *s = RLC_ALLOCA(int8_t, f);
gt_t q, w, *t = RLC_ALLOCA(gt_t, f * RLC_GT_TABLE);
bn_t n, u, *_b = RLC_ALLOCA(bn_t, f);
size_t l, *_l = RLC_ALLOCA(size_t, f);
size_t l, len, *_l = RLC_ALLOCA(size_t, f);

if (naf == NULL || t == NULL || _b == NULL || _l == NULL) {
if (reg == NULL || e == NULL || t == NULL || _b == NULL || _l == NULL) {
RLC_THROW(ERR_NO_MEMORY);
return;
}

if (bn_is_zero(b)) {
RLC_FREE(naf);
RLC_FREE(reg);
RLC_FREE(e);
RLC_FREE(s);
RLC_FREE(t);
RLC_FREE(_b);
Expand All @@ -291,11 +272,13 @@ void gt_exp_gls_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
bn_null(n);
bn_null(u);
gt_null(q);
gt_null(w);

RLC_TRY {
bn_new(n);
bn_new(u);
gt_new(q);
gt_new(w);
for (size_t i = 0; i < f; i++) {
bn_null(_b[i]);
bn_new(_b[i]);
Expand All @@ -321,49 +304,66 @@ void gt_exp_gls_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
bn_rec_frb(_b, f, _b[0], u, n, ep_curve_is_pairf() == EP_BN);

l = 0;
gt_copy(t[0], a);
len = bn_bits(u) + (ep_curve_is_pairf() == EP_BN);
for (size_t i = 0; i < f; i++) {
s[i] = bn_sign(_b[i]);
bn_abs(_b[i], _b[i]);
e[i] = bn_is_even(_b[i]);
_b[i]->dp[0] |= e[i];

_l[i] = RLC_FP_BITS + 1;
bn_rec_naf(naf + i * (RLC_FP_BITS + 1), &_l[i], _b[i], RLC_WIDTH);
bn_rec_reg(reg + i * (RLC_FP_BITS + 1), &_l[i], _b[i], len, RLC_WIDTH);
l = RLC_MAX(l, _l[i]);
/* Apply Frobenius before flipping sign to build table. */
if (i > 0) {
gt_psi(t[i * RLC_GT_TABLE], t[(i - 1) * RLC_GT_TABLE]);
}
}

for (size_t i = 0; i < f; i++) {
gt_inv(q, t[i * RLC_GT_TABLE]);
gt_copy_sec(q, t[i * RLC_GT_TABLE], s[i] == RLC_POS);
if (RLC_WIDTH > 2) {
gt_sqr(t[i * RLC_GT_TABLE], q);
gt_mul(t[i * RLC_GT_TABLE + 1], t[i * RLC_GT_TABLE], q);
for (size_t j = 2; j < RLC_GT_TABLE; j++) {
gt_mul(t[i * RLC_GT_TABLE + j], t[i * RLC_GT_TABLE + j - 1],
t[i * (RLC_GT_TABLE)]);
gt_copy(t[0], a);
gt_inv(q, t[0]);
gt_copy_sec(q, t[0], s[0] == RLC_POS);
if (RLC_WIDTH > 2) {
gt_sqr(t[0], q);
gt_mul(t[1], t[0], q);
for (size_t j = 2; j < RLC_GT_TABLE; j++) {
gt_mul(t[j], t[j - 1], t[0]);
}
}
gt_copy(t[0], q);
for (size_t i = 1; i < f; i++) {
for (size_t j = 0; j < RLC_GT_TABLE; j++) {
gt_frb(t[i * RLC_GT_TABLE + j],
t[(i - 1) * RLC_GT_TABLE + j], 1);
if (s[i] != s[i - 1]) {
gt_inv(t[i * RLC_GT_TABLE + j], t[i * RLC_GT_TABLE + j]);
}
}
gt_copy(t[i * RLC_GT_TABLE], q);
}

gt_set_unity(c);
for (int j = l - 1; j >= 0; j--) {
gt_sqr(c, c);
for (size_t i = 0; i < RLC_WIDTH - 1; i++) {
gt_sqr(c, c);
}

for (size_t i = 0; i < f; i++) {
n0 = naf[i * (RLC_FP_BITS + 1) + j];
if (n0 > 0) {
gt_mul(c, c, t[i * RLC_GT_TABLE + n0 / 2]);
}
if (n0 < 0) {
gt_inv(q, t[i * RLC_GT_TABLE - n0 / 2]);
gt_mul(c, c, q);
n0 = reg[i * (RLC_FP_BITS + 1) + j];
c0 = (n0 >> 7);
n0 = ((n0 ^ c0) - c0) >> 1;

for (size_t m = 0; m < RLC_GT_TABLE; m++) {
gt_copy_sec(w, t[i * RLC_GT_TABLE + m], m == n0);
}

gt_inv(q, w);
gt_copy_sec(q, w, c0 == 0);
gt_mul(c, c, q);

}
}

for (size_t i = 0; i < f; i++) {
/* Tables are built with points already negated, so no need here. */
gt_inv(q, t[i * RLC_GT_TABLE]);
gt_mul(q, c, q);
gt_copy_sec(c, q, e[i]);
}
}
RLC_CATCH_ANY {
RLC_THROW(ERR_CAUGHT);
Expand All @@ -372,13 +372,15 @@ void gt_exp_gls_imp(gt_t c, const gt_t a, const bn_t b, size_t f) {
bn_free(n);
bn_free(u);
gt_free(q);
gt_free(w);
for (size_t i = 0; i < f; i++) {
bn_free(_b[i]);
for (size_t j = 0; j < RLC_GT_TABLE; j++) {
gt_free(t[i * RLC_GT_TABLE + j]);
}
}
RLC_FREE(naf);
RLC_FREE(reg);
RLC_FREE(e);
RLC_FREE(s);
RLC_FREE(t);
RLC_FREE(_b);
Expand Down Expand Up @@ -522,7 +524,7 @@ void gt_exp_sec(gt_t c, const gt_t a, const bn_t b) {
}

#if FP_PRIME <= 1536
gt_exp_imp(c, a, b, ep_curve_frdim());
gt_exp_reg_gls(c, a, b, ep_curve_frdim());
#else
RLC_CAT(RLC_GT_LOWER, exp_monty)(c, a, b);
#endif
Expand Down

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