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Split ecmult table computation and printing

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This commit is contained in:
Pieter Wuille 2021-12-17 11:52:20 -05:00
parent 31feab053b
commit fc1bf9f15f
1 changed files with 45 additions and 25 deletions
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70
src/precompute_ecmult.c
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@ -20,24 +20,48 @@
#include "group_impl.h"
#include "ecmult.h"
void print_table(FILE *fp, const char *name, int window_g, const secp256k1_gej *gen, int with_conditionals) {
static secp256k1_gej gj;
static secp256k1_ge ge, dgen;
static secp256k1_ge_storage ges;
/* Construct table of all odd multiples of gen in range 1..(2**(window_g-1)-1). */
static void secp256k1_ecmult_compute_table(secp256k1_ge_storage* table, int window_g, const secp256k1_gej* gen) {
secp256k1_gej gj;
secp256k1_ge ge, dgen;
int j;
int i;
gj = *gen;
secp256k1_ge_set_gej_var(&ge, &gj);
secp256k1_ge_to_storage(&ges, &ge);
secp256k1_ge_to_storage(&table[0], &ge);
secp256k1_gej_double_var(&gj, gen, NULL);
secp256k1_ge_set_gej_var(&dgen, &gj);
for (j = 1; j < ECMULT_TABLE_SIZE(window_g); ++j) {
secp256k1_gej_set_ge(&gj, &ge);
secp256k1_gej_add_ge_var(&gj, &gj, &dgen, NULL);
secp256k1_ge_set_gej_var(&ge, &gj);
secp256k1_ge_to_storage(&table[j], &ge);
}
}
/* Like secp256k1_ecmult_compute_table, but one for both gen and gen*2^128. */
static void secp256k1_ecmult_compute_two_tables(secp256k1_ge_storage* table, secp256k1_ge_storage* table_128, int window_g, const secp256k1_ge* gen) {
secp256k1_gej gj;
int i;
secp256k1_gej_set_ge(&gj, gen);
secp256k1_ecmult_compute_table(table, window_g, &gj);
for (i = 0; i < 128; ++i) {
secp256k1_gej_double_var(&gj, &gj, NULL);
}
secp256k1_ecmult_compute_table(table_128, window_g, &gj);
}
static void print_table(FILE *fp, const char *name, int window_g, const secp256k1_ge_storage* table, int with_conditionals) {
int j;
int i;
fprintf(fp, "static const secp256k1_ge_storage %s[ECMULT_TABLE_SIZE(WINDOW_G)] = {\n", name);
fprintf(fp, " S(%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32
",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32")\n",
SECP256K1_GE_STORAGE_CONST_GET(ges));
secp256k1_gej_double_var(&gj, gen, NULL);
secp256k1_ge_set_gej_var(&dgen, &gj);
SECP256K1_GE_STORAGE_CONST_GET(table[0]));
j = 1;
for(i = 3; i <= window_g; ++i) {
@ -45,14 +69,9 @@ void print_table(FILE *fp, const char *name, int window_g, const secp256k1_gej *
fprintf(fp, "#if ECMULT_TABLE_SIZE(WINDOW_G) > %ld\n", ECMULT_TABLE_SIZE(i-1));
}
for(;j < ECMULT_TABLE_SIZE(i); ++j) {
secp256k1_gej_set_ge(&gj, &ge);
secp256k1_gej_add_ge_var(&gj, &gj, &dgen, NULL);
secp256k1_ge_set_gej_var(&ge, &gj);
secp256k1_ge_to_storage(&ges, &ge);
fprintf(fp, ",S(%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32
",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32")\n",
SECP256K1_GE_STORAGE_CONST_GET(ges));
SECP256K1_GE_STORAGE_CONST_GET(table[j]));
}
if (with_conditionals) {
fprintf(fp, "#endif\n");
@ -61,16 +80,17 @@ void print_table(FILE *fp, const char *name, int window_g, const secp256k1_gej *
fprintf(fp, "};\n");
}
void print_two_tables(FILE *fp, int window_g, const secp256k1_ge *g, int with_conditionals) {
secp256k1_gej gj;
int i;
static void print_two_tables(FILE *fp, int window_g, const secp256k1_ge *g, int with_conditionals) {
secp256k1_ge_storage* table = malloc(ECMULT_TABLE_SIZE(window_g) * sizeof(secp256k1_ge_storage));
secp256k1_ge_storage* table_128 = malloc(ECMULT_TABLE_SIZE(window_g) * sizeof(secp256k1_ge_storage));
secp256k1_gej_set_ge(&gj, g);
print_table(fp, "secp256k1_pre_g", window_g, &gj, with_conditionals);
for (i = 0; i < 128; ++i) {
secp256k1_gej_double_var(&gj, &gj, NULL);
}
print_table(fp, "secp256k1_pre_g_128", window_g, &gj, with_conditionals);
secp256k1_ecmult_compute_two_tables(table, table_128, window_g, g);
print_table(fp, "secp256k1_pre_g", window_g, table, with_conditionals);
print_table(fp, "secp256k1_pre_g_128", window_g, table_128, with_conditionals);
free(table);
free(table_128);
}
int main(void) {