// Get the base point order length
unsigned long BotanGOSTPrivateKey::getOrderLength() const
{
try
{
Botan::EC_Group group = BotanUtil::byteString2ECGroup(this->ec);
return group.get_order().bytes();
}
catch (...)
{
ERROR_MSG("Can't get EC group for order length");
return 0;
}
}
ticks ECDSA_Timing_Test::measure_critical_function(std::vector<uint8_t> input)
{
const Botan::BigInt k(input.data(), input.size());
const Botan::BigInt msg(5); // fixed message to minimize noise
ticks start = get_ticks();
//The following ECDSA operations involve and should not leak any information about k.
const Botan::BigInt k_inv = Botan::inverse_mod(k, m_group.get_order());
const Botan::PointGFp k_times_P = m_group.blinded_base_point_multiply(k, Timing_Test::timing_test_rng(), m_ws);
const Botan::BigInt r = m_group.mod_order(k_times_P.get_affine_x());
const Botan::BigInt s = m_group.multiply_mod_order(k_inv, mul_add(m_x, r, msg));
BOTAN_UNUSED(r, s);
ticks end = get_ticks();
return (end - start);
}