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[API BREAK] Introduce explicit contexts

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This commit is contained in:
Pieter Wuille
2015-02-03 17:27:00 -08:00
parent a0d3b89dd6
commit a9b6595ef8
14 changed files with 345 additions and 280 deletions
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57
src/ecmult_impl.h
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@@ -92,59 +92,55 @@ static void secp256k1_ecmult_table_precomp_ge_storage_var(secp256k1_ge_storage_t
} \
} while(0)
typedef struct {
/* For accelerating the computation of a*P + b*G: */
secp256k1_ge_storage_t pre_g[ECMULT_TABLE_SIZE(WINDOW_G)]; /* odd multiples of the generator */
static void secp256k1_ecmult_context_init(secp256k1_ecmult_context_t *ctx) {
ctx->pre_g = NULL;
#ifdef USE_ENDOMORPHISM
secp256k1_ge_storage_t pre_g_128[ECMULT_TABLE_SIZE(WINDOW_G)]; /* odd multiples of 2^128*generator */
ctx->pre_g_128 = NULL;
#endif
} secp256k1_ecmult_consts_t;
}
static const secp256k1_ecmult_consts_t *secp256k1_ecmult_consts = NULL;
static void secp256k1_ecmult_start(void) {
static void secp256k1_ecmult_context_build(secp256k1_ecmult_context_t *ctx) {
secp256k1_gej_t gj;
secp256k1_ecmult_consts_t *ret;
if (secp256k1_ecmult_consts != NULL) {
if (ctx->pre_g != NULL) {
return;
}
/* Allocate the precomputation table. */
ret = (secp256k1_ecmult_consts_t*)checked_malloc(sizeof(secp256k1_ecmult_consts_t));
/* get the generator */
secp256k1_gej_set_ge(&gj, &secp256k1_ge_const_g);
ctx->pre_g = (secp256k1_ge_storage_t (*)[])checked_malloc(sizeof((*ctx->pre_g)[0]) * ECMULT_TABLE_SIZE(WINDOW_G));
/* precompute the tables with odd multiples */
secp256k1_ecmult_table_precomp_ge_storage_var(ret->pre_g, &gj, WINDOW_G);
secp256k1_ecmult_table_precomp_ge_storage_var(*ctx->pre_g, &gj, WINDOW_G);
#ifdef USE_ENDOMORPHISM
{
secp256k1_gej_t g_128j;
int i;
ctx->pre_g_128 = (secp256k1_ge_storage_t (*)[])checked_malloc(sizeof((*ctx->pre_g_128)[0]) * ECMULT_TABLE_SIZE(WINDOW_G));
/* calculate 2^128*generator */
g_128j = gj;
for (i = 0; i < 128; i++) {
secp256k1_gej_double_var(&g_128j, &g_128j);
}
secp256k1_ecmult_table_precomp_ge_storage_var(ret->pre_g_128, &g_128j, WINDOW_G);
secp256k1_ecmult_table_precomp_ge_storage_var(*ctx->pre_g_128, &g_128j, WINDOW_G);
}
#endif
/* Set the global pointer to the precomputation table. */
secp256k1_ecmult_consts = ret;
}
static void secp256k1_ecmult_stop(void) {
secp256k1_ecmult_consts_t *c;
if (secp256k1_ecmult_consts == NULL) {
return;
}
static int secp256k1_ecmult_context_is_built(const secp256k1_ecmult_context_t *ctx) {
return ctx->pre_g != NULL;
}
c = (secp256k1_ecmult_consts_t*)secp256k1_ecmult_consts;
secp256k1_ecmult_consts = NULL;
free(c);
static void secp256k1_ecmult_context_clear(secp256k1_ecmult_context_t *ctx) {
free(ctx->pre_g);
#ifdef USE_ENDOMORPHISM
free(ctx->pre_g_128);
#endif
secp256k1_ecmult_context_init(ctx);
}
/** Convert a number to WNAF notation. The number becomes represented by sum(2^i * wnaf[i], i=0..bits),
@@ -191,11 +187,10 @@ static int secp256k1_ecmult_wnaf(int *wnaf, const secp256k1_scalar_t *a, int w)
return set_bits;
}
static void secp256k1_ecmult(secp256k1_gej_t *r, const secp256k1_gej_t *a, const secp256k1_scalar_t *na, const secp256k1_scalar_t *ng) {
static void secp256k1_ecmult(const secp256k1_ecmult_context_t *ctx, secp256k1_gej_t *r, const secp256k1_gej_t *a, const secp256k1_scalar_t *na, const secp256k1_scalar_t *ng) {
secp256k1_gej_t tmpj;
secp256k1_gej_t pre_a[ECMULT_TABLE_SIZE(WINDOW_A)];
secp256k1_ge_t tmpa;
const secp256k1_ecmult_consts_t *c = secp256k1_ecmult_consts;
#ifdef USE_ENDOMORPHISM
secp256k1_gej_t pre_a_lam[ECMULT_TABLE_SIZE(WINDOW_A)];
secp256k1_scalar_t na_1, na_lam;
@@ -279,11 +274,11 @@ static void secp256k1_ecmult(secp256k1_gej_t *r, const secp256k1_gej_t *a, const
secp256k1_gej_add_var(r, r, &tmpj);
}
if (i < bits_ng_1 && (n = wnaf_ng_1[i])) {
ECMULT_TABLE_GET_GE_STORAGE(&tmpa, c->pre_g, n, WINDOW_G);
ECMULT_TABLE_GET_GE_STORAGE(&tmpa, *ctx->pre_g, n, WINDOW_G);
secp256k1_gej_add_ge_var(r, r, &tmpa);
}
if (i < bits_ng_128 && (n = wnaf_ng_128[i])) {
ECMULT_TABLE_GET_GE_STORAGE(&tmpa, c->pre_g_128, n, WINDOW_G);
ECMULT_TABLE_GET_GE_STORAGE(&tmpa, *ctx->pre_g_128, n, WINDOW_G);
secp256k1_gej_add_ge_var(r, r, &tmpa);
}
#else
@@ -292,7 +287,7 @@ static void secp256k1_ecmult(secp256k1_gej_t *r, const secp256k1_gej_t *a, const
secp256k1_gej_add_var(r, r, &tmpj);
}
if (i < bits_ng && (n = wnaf_ng[i])) {
ECMULT_TABLE_GET_GE_STORAGE(&tmpa, c->pre_g, n, WINDOW_G);
ECMULT_TABLE_GET_GE_STORAGE(&tmpa, *ctx->pre_g, n, WINDOW_G);
secp256k1_gej_add_ge_var(r, r, &tmpa);
}
#endif