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Add ge25519_p2_to_p3(), ge25519_p3_add(), ge25519_p3_sub()

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This commit is contained in:
Frank Denis 2022-11-26 22:14:24 +01:00
parent 42b4a295fc
commit d2d8f573b7
4 changed files with 48 additions and 11 deletions
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34
src/libsodium/crypto_core/ed25519/ref10/ed25519_ref10.c
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@ -471,6 +471,18 @@ ge25519_p1p1_to_p3(ge25519_p3 *r, const ge25519_p1p1 *p)
fe25519_mul(r->T, p->X, p->Y);
}
/*
r = p
*/
void
ge25519_p2_to_p3(ge25519_p3 *r, const ge25519_p2 *p)
{
fe25519_copy(r->X, p->X);
fe25519_copy(r->Y, p->Y);
fe25519_copy(r->Z, p->Z);
fe25519_mul(r->T, p->X, p->Y);
}
static void
ge25519_p2_0(ge25519_p2 *h)
{
@ -988,8 +1000,18 @@ ge25519_p3p3_dbl(ge25519_p3 *r, const ge25519_p3 *p)
ge25519_p1p1_to_p3(r, &p1p1);
}
/* r = p+q */
/* r = -p */
static void
ge25519_p3_neg(ge25519_p3 *r, const ge25519_p3 *p)
{
fe25519_neg(r->X, p->X);
fe25519_copy(r->Y, p->Y);
fe25519_copy(r->Z, p->Z);
fe25519_neg(r->T, p->T);
}
/* r = p+q */
void
ge25519_p3_add(ge25519_p3 *r, const ge25519_p3 *p, const ge25519_p3 *q)
{
ge25519_cached q_cached;
@ -1000,6 +1022,16 @@ ge25519_p3_add(ge25519_p3 *r, const ge25519_p3 *p, const ge25519_p3 *q)
ge25519_p1p1_to_p3(r, &p1p1);
}
/* r = p-q */
void
ge25519_p3_sub(ge25519_p3 *r, const ge25519_p3 *p, const ge25519_p3 *q)
{
ge25519_p3 q_neg;
ge25519_p3_neg(&q_neg, q);
ge25519_p3_add(r, p, &q_neg);
}
/* r = r*(2^n)+q */
static void
ge25519_p3_dbladd(ge25519_p3 *r, const int n, const ge25519_p3 *q)

18
src/libsodium/crypto_sign/ed25519/ref10/open.c
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@ -24,8 +24,8 @@ _crypto_sign_ed25519_verify_detached(const unsigned char *sig,
ge25519_p3 check;
ge25519_p3 expected_r;
ge25519_p3 A;
ge25519_p2 sb_ah;
ge25519_cached sb_ah_;
ge25519_p3 sb_ah;
ge25519_p2 sb_ah_p2;
ACQUIRE_FENCE;
#ifdef ED25519_COMPAT
@ -48,6 +48,9 @@ _crypto_sign_ed25519_verify_detached(const unsigned char *sig,
if (ge25519_frombytes_negate_vartime(&A, pk) != 0) {
return -1;
}
if (ge25519_frombytes(&expected_r, sig) != 0) {
return -1;
}
_crypto_sign_ed25519_ref10_hinit(&hs, prehashed);
crypto_hash_sha512_update(&hs, sig, 32);
crypto_hash_sha512_update(&hs, pk, 32);
@ -55,14 +58,9 @@ _crypto_sign_ed25519_verify_detached(const unsigned char *sig,
crypto_hash_sha512_final(&hs, h);
sc25519_reduce(h);
ge25519_double_scalarmult_vartime(&sb_ah_, h, &A, sig + 32);
if (ge25519_frombytes(&expected_r, sig) != 0) {
return -1;
}
ge25519_p3_to_cached(&sb_ah, &sb_ah_);
ge25519_sub_cached(&check, &expected_r, &sb_ah);
ge25519_double_scalarmult_vartime(&sb_ah_p2, h, &A, sig + 32);
ge25519_p2_to_p3(&sb_ah, &sb_ah_p2);
ge25519_p3_sub(&check, &expected_r, &sb_ah);
ge25519_clear_cofactor(&check);
return fe25519_iszero(check.X) - 1;

6
src/libsodium/include/sodium/private/ed25519_ref10.h
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@ -89,10 +89,16 @@ void ge25519_p1p1_to_p2(ge25519_p2 *r, const ge25519_p1p1 *p);
void ge25519_p1p1_to_p3(ge25519_p3 *r, const ge25519_p1p1 *p);
void ge25519_p2_to_p3(ge25519_p3 *r, const ge25519_p2 *p);
void ge25519_add_cached(ge25519_p1p1 *r, const ge25519_p3 *p, const ge25519_cached *q);
void ge25519_sub_cached(ge25519_p1p1 *r, const ge25519_p3 *p, const ge25519_cached *q);
void ge25519_p3_add(ge25519_p3 *r, const ge25519_p3 *p, const ge25519_p3 *q);
void ge25519_p3_sub(ge25519_p3 *r, const ge25519_p3 *p, const ge25519_p3 *q);
void ge25519_scalarmult_base(ge25519_p3 *h, const unsigned char *a);
void ge25519_double_scalarmult_vartime(ge25519_p2 *r, const unsigned char *a,

1
test/default/sign2.exp
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@ -0,0 +1 @@
OK