Skip to content

Initialize field elements when resulting in infinity #699

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Sep 9, 2020
Merged

Initialize field elements when resulting in infinity #699

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
61d1ecb
Added test with additions resulting in infinity
elichai Dec 10, 2019
47a7b83
Clear field elements when writing infinity
elichai Dec 10, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 3 additions & 3 deletions src/group_impl.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -397,7 +397,7 @@ static void secp256k1_gej_add_var(secp256k1_gej *r, const secp256k1_gej *a, cons
if (rzr != NULL) {
secp256k1_fe_set_int(rzr, 0);
}
r->infinity = 1;
secp256k1_gej_set_infinity(r);
}
return;
}
Expand Down Expand Up @@ -447,7 +447,7 @@ static void secp256k1_gej_add_ge_var(secp256k1_gej *r, const secp256k1_gej *a, c
if (rzr != NULL) {
secp256k1_fe_set_int(rzr, 0);
}
r->infinity = 1;
secp256k1_gej_set_infinity(r);
}
return;
}
Expand Down Expand Up @@ -506,7 +506,7 @@ static void secp256k1_gej_add_zinv_var(secp256k1_gej *r, const secp256k1_gej *a,
if (secp256k1_fe_normalizes_to_zero_var(&i)) {
secp256k1_gej_double_var(r, a, NULL);
} else {
r->infinity = 1;
secp256k1_gej_set_infinity(r);
}
return;
}
Expand Down
34 changes: 34 additions & 0 deletions src/tests.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2258,6 +2258,39 @@ void test_ge(void) {
free(zinv);
}


void test_intialized_inf(void) {
secp256k1_ge p;
secp256k1_gej pj, npj, infj1, infj2, infj3;
secp256k1_fe zinv;

/* Test that adding P+(-P) results in a fully initalized infinity*/
random_group_element_test(&p);
secp256k1_gej_set_ge(&pj, &p);
secp256k1_gej_neg(&npj, &pj);

secp256k1_gej_add_var(&infj1, &pj, &npj, NULL);
CHECK(secp256k1_gej_is_infinity(&infj1));
CHECK(secp256k1_fe_is_zero(&infj1.x));
CHECK(secp256k1_fe_is_zero(&infj1.y));
CHECK(secp256k1_fe_is_zero(&infj1.z));

secp256k1_gej_add_ge_var(&infj2, &npj, &p, NULL);
CHECK(secp256k1_gej_is_infinity(&infj2));
CHECK(secp256k1_fe_is_zero(&infj2.x));
CHECK(secp256k1_fe_is_zero(&infj2.y));
CHECK(secp256k1_fe_is_zero(&infj2.z));

secp256k1_fe_set_int(&zinv, 1);
secp256k1_gej_add_zinv_var(&infj3, &npj, &p, &zinv);
CHECK(secp256k1_gej_is_infinity(&infj3));
CHECK(secp256k1_fe_is_zero(&infj3.x));
CHECK(secp256k1_fe_is_zero(&infj3.y));
CHECK(secp256k1_fe_is_zero(&infj3.z));


}

void test_add_neg_y_diff_x(void) {
/* The point of this test is to check that we can add two points
* whose y-coordinates are negatives of each other but whose x
Expand Down Expand Up @@ -2331,6 +2364,7 @@ void run_ge(void) {
test_ge();
}
test_add_neg_y_diff_x();
test_intialized_inf();
}

void test_ec_combine(void) {
Expand Down