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opti: rm malloc in mul and useless cmp in modulo

This commit is contained in:
gbrochar 2024-02-18 17:14:48 +01:00
parent 365c98be7c
commit 1d9e2936ac
1 changed files with 36 additions and 17 deletions
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53
rsa/bigint.c
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@ -106,11 +106,10 @@ void custom_bigint_modulo(bigint_t a, bigint_t b, bigint_t result, bigint_t mod,
if (bigint_cmp(result, b) < 0) {
return ;
}
bigint_bitwise_left_shift(mod);
while (bigint_cmp(result, mod) > 0) {
bigint_bitwise_left_shift(mod);
}
while (bigint_cmp(b, mod) < 0) {
while (bigint_cmp(result, mod) > 0) {
bigint_bitwise_left_shift(mod);
}
bigint_bitwise_right_shift(mod);
if (bigint_cmp(result, mod) > 0) {
bigint_substraction(result, mod, borrow_sub, y_sub);
@ -175,17 +174,13 @@ void bigint_set_zeros(bigint_t n) {
}
}
void custom_bigint_mul(bigint_t a, bigint_t b, bigint_t result) {
void custom_bigint_mul(bigint_t a, bigint_t b, bigint_t result, bigint_t *b_tool) {
int width = a.len * 32;
bigint_set_zeros(result);
bigint_t *b_tool = (bigint_t *)malloc(32 * sizeof(bigint_t));
b_tool[0] = bigint_zero(a.len + b.len);
bigint_set_zeros(b_tool[0]);
memcpy(b_tool[0].data, b.data, b.len * sizeof(uint32_t));
for (int i = 1; i < 32; i++) {
b_tool[i] = bigint_zero(a.len + b.len);
bigint_set_zeros(b_tool[i]);
memcpy(b_tool[i].data, b_tool[i - 1].data, b.len * sizeof(uint32_t));
bigint_bitwise_left_shift(b_tool[i]);
@ -198,14 +193,11 @@ void custom_bigint_mul(bigint_t a, bigint_t b, bigint_t result) {
custom_bigint_add(result, b_tool[offset], index);
}
}
for (int i = 0; i < 32; i++) {
bigint_destroy(b_tool[i]);
}
}
// a^e mod n
// clean memory tricks !!!
void custom_bigint_pow_mod(bigint_t a, bigint_t e, bigint_t n, bigint_t result, bigint_t custom, bigint_t custom2, bigint_t mod, bigint_t borrow_sub, bigint_t y_sub) {
void custom_bigint_pow_mod(bigint_t a, bigint_t e, bigint_t n, bigint_t result, bigint_t custom, bigint_t custom2, bigint_t mod, bigint_t borrow_sub, bigint_t y_sub, bigint_t *b_tool) {
bigint_set_zeros(result);
bigint_set_zeros(custom);
bigint_set_zeros(custom2);
@ -217,12 +209,12 @@ void custom_bigint_pow_mod(bigint_t a, bigint_t e, bigint_t n, bigint_t result,
}
cursor--;
while (cursor >= 0) {
custom_bigint_mul(result, result, custom);
custom_bigint_mul(result, result, custom, b_tool);
custom_bigint_modulo(custom, n, custom2, mod, borrow_sub, y_sub);
bigint_set_zeros(result);
memcpy(result.data, custom2.data, custom2.len * sizeof(uint32_t));
if (e.data[cursor / 32] & 1 << (cursor % 32)) {
custom_bigint_mul(result, a, custom);
custom_bigint_mul(result, a, custom, b_tool);
custom_bigint_modulo(custom, n, custom2, mod, borrow_sub, y_sub);
memcpy(result.data, custom2.data, custom2.len * sizeof(uint32_t));
}
@ -269,6 +261,12 @@ bigint_t bigint_prime(size_t len) {
bigint_t y = bigint_zero(RSA_BLOCK_SIZE / 8 / sizeof(uint32_t) * 2);
bigint_t custom = bigint_zero(RSA_BLOCK_SIZE / 8 / sizeof(uint32_t) * 2);
bigint_t custom2 = bigint_zero(RSA_BLOCK_SIZE / 8 / sizeof(uint32_t) * 2);
bigint_t *b_tool = (bigint_t *)protected_malloc(32 * sizeof(bigint_t));
for (int i = 0; i < 32; i++) {
b_tool[i] = bigint_zero(RSA_BLOCK_SIZE / 8 / sizeof(uint32_t) * 4);
}
bigint_t two = bigint_zero(RSA_BLOCK_SIZE / 8 / sizeof(uint32_t) * 2);
bigint_t one = bigint_zero(RSA_BLOCK_SIZE / 8 / sizeof(uint32_t) * 2);
@ -285,14 +283,21 @@ bigint_t bigint_prime(size_t len) {
while (bigint_cmp(a, two) < 0 || bigint_cmp(a, n_minus_two) > 0) {
bigint_set_random_bytes(a, len);
}
custom_bigint_pow_mod(a, d, n, x, custom, custom2, mod, borrow_sub, y_sub);
custom_bigint_pow_mod(a, d, n, x, custom, custom2, mod, borrow_sub, y_sub, b_tool);
for (uint32_t i = 0; i < s; i++) {
custom_bigint_pow_mod(x, two, n, y, custom, custom2, mod, borrow_sub, y_sub);
custom_bigint_pow_mod(x, two, n, y, custom, custom2, mod, borrow_sub, y_sub, b_tool);
if (!bigint_dif(y, one) && bigint_dif(x, one) && bigint_dif(x, n_minus_one)) {
bulk_destroy(x, y, n, d, two, one, n_minus_two, n_minus_one);
bigint_destroy(custom);
bigint_destroy(custom2);
bigint_destroy(a);
bigint_destroy(mod);
bigint_destroy(borrow_sub);
bigint_destroy(y_sub);
for (int i = 0; i < 32; i++) {
bigint_destroy(b_tool[i]);
}
free(b_tool);
return bigint_prime(len);
}
bigint_destroy(x);
@ -303,12 +308,26 @@ bigint_t bigint_prime(size_t len) {
bigint_destroy(custom);
bigint_destroy(custom2);
bigint_destroy(a);
bigint_destroy(mod);
bigint_destroy(borrow_sub);
bigint_destroy(y_sub);
for (int i = 0; i < 32; i++) {
bigint_destroy(b_tool[i]);
}
free(b_tool);
return bigint_prime(len);
}
}
bulk_destroy(x, y, custom, d, two, one, n_minus_two, n_minus_one);
bigint_destroy(custom2);
bigint_destroy(a);
bigint_destroy(mod);
bigint_destroy(borrow_sub);
bigint_destroy(y_sub);
for (int i = 0; i < 32; i++) {
bigint_destroy(b_tool[i]);
}
free(b_tool);
return n;
}