void Evaluator::multiply(const BigPoly &encrypted1, const BigPoly &encrypted2, BigPoly &destination)
{
// Extract encryption parameters.
int coeff_count = poly_modulus_.coeff_count();
int coeff_bit_count = poly_modulus_.coeff_bit_count();
int coeff_uint64_count = divide_round_up(coeff_bit_count, bits_per_uint64);
// Verify parameters.
if (encrypted1.coeff_count() != coeff_count || encrypted1.coeff_bit_count() != coeff_bit_count)
{
throw invalid_argument("encrypted1 is not valid for encryption parameters");
}
if (encrypted2.coeff_count() != coeff_count || encrypted2.coeff_bit_count() != coeff_bit_count)
{
throw invalid_argument("encrypted2 is not valid for encryption parameters");
}
#ifdef _DEBUG
if (encrypted1.significant_coeff_count() == coeff_count || !are_poly_coefficients_less_than(encrypted1, coeff_modulus_))
{
throw invalid_argument("encrypted1 is not valid for encryption parameters");
}
if (encrypted2.significant_coeff_count() == coeff_count || !are_poly_coefficients_less_than(encrypted2, coeff_modulus_))
{
throw invalid_argument("encrypted2 is not valid for encryption parameters");
}
#endif
if (destination.coeff_count() != coeff_count || destination.coeff_bit_count() != coeff_bit_count)
{
destination.resize(coeff_count, coeff_bit_count);
}
// Handle test-mode case.
if (mode_ == TEST_MODE)
{
// Get pointer to inputs (duplicated if needed).
ConstPointer encrypted1ptr = duplicate_poly_if_needed(encrypted1, encrypted1.pointer() == destination.pointer(), pool_);
ConstPointer encrypted2ptr = duplicate_poly_if_needed(encrypted2, encrypted2.pointer() == destination.pointer(), pool_);
multiply_poly_poly_polymod_coeffmod(encrypted1ptr.get(), encrypted2ptr.get(), polymod_, mod_, destination.pointer(), pool_);
return;
}
// Multiply encrypted polynomials and perform key switching.
Pointer product(allocate_poly(coeff_count, coeff_uint64_count, pool_));
multiply(encrypted1.pointer(), encrypted2.pointer(), product.get());
relinearize(product.get(), destination.pointer());
}
void poly_eval_poly_polymod_coeffmod(const BigPoly &poly_to_evaluate, const BigPoly &poly_to_evaluate_at,
const BigPoly &poly_modulus, const BigUInt &coeff_modulus, BigPoly &destination, const MemoryPoolHandle &pool)
{
if (!pool)
{
throw invalid_argument("pool is uninitialized");
}
if (poly_to_evaluate.significant_coeff_count() > poly_modulus.coeff_count() ||
poly_to_evaluate.significant_coeff_bit_count() > coeff_modulus.significant_bit_count())
{
throw invalid_argument("poly_to_evaluate is not reduced");
}
if (poly_to_evaluate_at.significant_coeff_count() > poly_modulus.coeff_count() ||
poly_to_evaluate_at.significant_coeff_bit_count() > coeff_modulus.significant_bit_count())
{
throw invalid_argument("poly_to_evaluate_at is not reduced");
}
int poly_to_eval_coeff_uint64_count = poly_to_evaluate.coeff_uint64_count();
int coeff_modulus_bit_count = coeff_modulus.significant_bit_count();
if (poly_to_evaluate.is_zero())
{
destination.set_zero();
}
if (poly_to_evaluate_at.is_zero())
{
destination.resize(1, coeff_modulus_bit_count);
modulo_uint(poly_to_evaluate.data(), poly_to_eval_coeff_uint64_count,
Modulus(coeff_modulus.data(), coeff_modulus.uint64_count(), pool),
destination.data(), pool);
return;
}
ConstPointer poly_to_eval_ptr = duplicate_poly_if_needed(poly_to_evaluate, poly_modulus.coeff_count(), coeff_modulus.uint64_count(), false, pool);
ConstPointer poly_to_eval_at_ptr = duplicate_poly_if_needed(poly_to_evaluate_at, poly_modulus.coeff_count(), coeff_modulus.uint64_count(), false, pool);
destination.resize(poly_modulus.coeff_count(), coeff_modulus_bit_count);
util::poly_eval_poly_polymod_coeffmod(poly_to_eval_ptr.get(), poly_to_eval_at_ptr.get(),
PolyModulus(poly_modulus.data(), poly_modulus.coeff_count(), poly_modulus.coeff_uint64_count()),
Modulus(coeff_modulus.data(), coeff_modulus.uint64_count(), pool),
destination.data(), pool);
}
void exponentiate_poly_polymod_coeffmod(const BigPoly &operand, const BigUInt &exponent,
const BigPoly &poly_modulus, const BigUInt &coeff_modulus, BigPoly &destination, const MemoryPoolHandle &pool)
{
if (operand.significant_coeff_count() > poly_modulus.coeff_count() ||
operand.significant_coeff_bit_count() > coeff_modulus.significant_bit_count())
{
throw invalid_argument("operand is not reduced");
}
if (exponent < 0)
{
throw invalid_argument("exponent must be a non-negative integer");
}
if (operand.is_zero() && exponent == 0)
{
throw invalid_argument("undefined operation");
}
if (!pool)
{
throw invalid_argument("pool is uninitialized");
}
if (operand.is_zero())
{
destination.set_zero();
return;
}
if (destination.coeff_bit_count() != coeff_modulus.significant_bit_count() ||
destination.coeff_count() != poly_modulus.coeff_count())
{
destination.resize(poly_modulus.coeff_count(), coeff_modulus.significant_bit_count());
}
ConstPointer operand_ptr = duplicate_poly_if_needed(operand, poly_modulus.coeff_count(), coeff_modulus.uint64_count(), false, pool);
util::exponentiate_poly_polymod_coeffmod(operand_ptr.get(), exponent.data(), exponent.uint64_count(),
PolyModulus(poly_modulus.data(), poly_modulus.coeff_count(), poly_modulus.coeff_uint64_count()),
Modulus(coeff_modulus.data(), coeff_modulus.uint64_count(), pool),
destination.data(), pool);
}
void Evaluator::relinearize(const BigPoly &encrypted, BigPoly &destination)
{
// Extract encryption parameters.
int coeff_count = poly_modulus_.coeff_count();
int coeff_bit_count = poly_modulus_.coeff_bit_count();
int coeff_uint64_count = divide_round_up(coeff_bit_count, bits_per_uint64);
// Verify parameters.
if (encrypted.coeff_count() != coeff_count || encrypted.coeff_bit_count() != coeff_bit_count)
{
throw invalid_argument("encrypted is not valid for encryption parameters");
}
#ifdef _DEBUG
if (encrypted.significant_coeff_count() == coeff_count || !are_poly_coefficients_less_than(encrypted, coeff_modulus_))
{
throw invalid_argument("encrypted is not valid for encryption parameters");
}
#endif
if (destination.coeff_count() != coeff_count || destination.coeff_bit_count() != coeff_bit_count)
{
destination.resize(coeff_count, coeff_bit_count);
}
// Handle test-mode case.
if (mode_ == TEST_MODE)
{
set_poly_poly(encrypted.pointer(), coeff_count, coeff_uint64_count, destination.pointer());
return;
}
// Get pointer to inputs (duplicated if needed).
ConstPointer encryptedptr = duplicate_poly_if_needed(encrypted, encrypted.pointer() == destination.pointer(), pool_);
// Relinearize polynomial.
relinearize(encryptedptr.get(), destination.pointer());
}
void Evaluator::multiply_plain(const BigPoly &encrypted1, const BigPoly &plain2, BigPoly &destination)
{
// Extract encryption parameters.
int coeff_count = poly_modulus_.coeff_count();
int coeff_bit_count = poly_modulus_.coeff_bit_count();
int coeff_uint64_count = divide_round_up(coeff_bit_count, bits_per_uint64);
// Verify parameters.
if (encrypted1.coeff_count() != coeff_count || encrypted1.coeff_bit_count() != coeff_bit_count)
{
throw invalid_argument("encrypted1 is not valid for encryption parameters");
}
#ifdef _DEBUG
if (encrypted1.significant_coeff_count() == coeff_count || !are_poly_coefficients_less_than(encrypted1, coeff_modulus_))
{
throw invalid_argument("encrypted1 is not valid for encryption parameters");
}
if (plain2.significant_coeff_count() >= coeff_count || !are_poly_coefficients_less_than(plain2, plain_modulus_))
{
throw invalid_argument("plain2 is too large to be represented by encryption parameters");
}
#endif
if (destination.coeff_count() != coeff_count || destination.coeff_bit_count() != coeff_bit_count)
{
destination.resize(coeff_count, coeff_bit_count);
}
// Get pointer to inputs (duplicated if needed).
ConstPointer encrypted1ptr = duplicate_poly_if_needed(encrypted1, encrypted1.pointer() == destination.pointer(), pool_);
// Handle test-mode case.
if (mode_ == TEST_MODE)
{
// Get pointer to inputs (duplicated and resized if needed).
ConstPointer plain2ptr = duplicate_poly_if_needed(plain2, coeff_count, coeff_uint64_count, plain2.pointer() == destination.pointer(), pool_);
// Resize second operand if needed.
multiply_poly_poly_polymod_coeffmod(encrypted1ptr.get(), plain2ptr.get(), polymod_, mod_, destination.pointer(), pool_);
return;
}
// Reposition coefficients.
Pointer moved2ptr(allocate_poly(coeff_count, coeff_uint64_count, pool_));
int plain_coeff_count = min(plain2.significant_coeff_count(), coeff_count);
int plain2_coeff_uint64_count = plain2.coeff_uint64_count();
const uint64_t *plain2_coeff = plain2.pointer();
uint64_t *moved2_coeff = moved2ptr.get();
for (int i = 0; i < plain_coeff_count; ++i)
{
set_uint_uint(plain2_coeff, plain2_coeff_uint64_count, coeff_uint64_count, moved2_coeff);
bool is_upper_half = is_greater_than_or_equal_uint_uint(moved2_coeff, plain_upper_half_threshold_.pointer(), coeff_uint64_count);
if (is_upper_half)
{
add_uint_uint(moved2_coeff, plain_upper_half_increment_.pointer(), coeff_uint64_count, moved2_coeff);
}
moved2_coeff += coeff_uint64_count;
plain2_coeff += plain2_coeff_uint64_count;
}
for (int i = plain_coeff_count; i < coeff_count; ++i)
{
set_zero_uint(coeff_uint64_count, moved2_coeff);
moved2_coeff += coeff_uint64_count;
}
// Use normal polynomial multiplication.
multiply_poly_poly_polymod_coeffmod(encrypted1ptr.get(), moved2ptr.get(), polymod_, mod_, destination.pointer(), pool_);
}
