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crypto: implemented point_t::operator-() + test

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sowle 2023-08-23 19:32:28 +02:00
parent 57a7cf8451
commit 8fdd15f584
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2 changed files with 40 additions and 0 deletions
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9
src/crypto/crypto-sugar.h
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@ -727,6 +727,15 @@ namespace crypto
return result;
}
point_t operator-() const
{
point_t result = *this;
fe zero = {0};
fe_sub(result.m_p3.Y, zero, result.m_p3.Y);
fe_sub(result.m_p3.Z, zero, result.m_p3.Z);
return result;
}
point_t& modify_mul8()
{
ge_mul8_p3(&m_p3, &m_p3);

31
tests/functional_tests/crypto_tests.cpp
View file

@ -1588,6 +1588,37 @@ TEST(crypto, schnorr_sig)
return true;
}
TEST(crypto, point_negation)
{
ASSERT_EQ(c_point_0, -c_point_0);
ASSERT_NEQ(c_point_G, -c_point_G);
ASSERT_EQ(c_point_G, -(-c_point_G));
ASSERT_EQ(-c_point_G, c_scalar_Lm1 * c_point_G);
ASSERT_EQ(-c_point_G, c_point_0 - c_point_G);
ASSERT_EQ(0 * (-c_point_G), c_point_0);
scalar_t a = scalar_t::random(), b = scalar_t::random();
ASSERT_EQ(a * (-c_point_G) + b * c_point_G + a * c_point_H + b * (-c_point_H), (b - a) * c_point_G + (a - b) * c_point_H);
ASSERT_EQ(a * (-c_point_G), (a * c_scalar_Lm1) * c_point_G);
for(size_t i = 0, sz = sizeof(canonical_torsion_elements) / sizeof(canonical_torsion_elements[0]); i < sz; ++i)
{
point_t el{};
ASSERT_TRUE(el.from_string(canonical_torsion_elements[i].string));
ASSERT_EQ(el, -(-el));
ASSERT_EQ((-scalar_t(1)) * el, (c_scalar_0 - c_scalar_1) * el);
ASSERT_NEQ(-el, (-scalar_t(1)) * el); // because torsion elements have order != L
ASSERT_NEQ(-el, c_scalar_Lm1 * el); // because torsion elements have order != L
ASSERT_EQ(-el, (scalar_t(canonical_torsion_elements[i].order) - 1) * el); // they rather have order == canonical_torsion_elements[i].order
ASSERT_EQ(-el, c_point_0 - el);
ASSERT_EQ((-el) + (el), c_point_0);
ASSERT_EQ((-el) - (-el), c_point_0);
scalar_t x = scalar_t::random();
ASSERT_EQ(x * (-el) + x * el, c_point_0);
}
return true;
}
//
// test's runner