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// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license.
#pragma once
#include "seal/util/defines.h"
#include <cstddef>
namespace seal
{
namespace util
{
/**
Largest allowed bit counts for coeff_modulus based on the security estimates from
HomomorphicEncryption.org security standard. Microsoft SEAL samples the secret key
from a ternary {-1, 0, 1} distribution.
*/
// Ternary secret; 128 bits classical security
SEAL_NODISCARD constexpr int seal_he_std_parms_128_tc(std::size_t poly_modulus_degree) noexcept
{
switch (poly_modulus_degree)
{
case std::size_t(1024):
return 27;
case std::size_t(2048):
return 54;
case std::size_t(4096):
return 109;
case std::size_t(8192):
return 218;
case std::size_t(16384):
return 438;
case std::size_t(32768):
return 881;
}
return 0;
}
// Ternary secret; 192 bits classical security
SEAL_NODISCARD constexpr int seal_he_std_parms_192_tc(std::size_t poly_modulus_degree) noexcept
{
switch (poly_modulus_degree)
{
case std::size_t(1024):
return 19;
case std::size_t(2048):
return 37;
case std::size_t(4096):
return 75;
case std::size_t(8192):
return 152;
case std::size_t(16384):
return 305;
case std::size_t(32768):
return 611;
}
return 0;
}
// Ternary secret; 256 bits classical security
SEAL_NODISCARD constexpr int seal_he_std_parms_256_tc(std::size_t poly_modulus_degree) noexcept
{
switch (poly_modulus_degree)
{
case std::size_t(1024):
return 14;
case std::size_t(2048):
return 29;
case std::size_t(4096):
return 58;
case std::size_t(8192):
return 118;
case std::size_t(16384):
return 237;
case std::size_t(32768):
return 476;
}
return 0;
}
// Ternary secret; 128 bits quantum security
SEAL_NODISCARD constexpr int seal_he_std_parms_128_tq(std::size_t poly_modulus_degree) noexcept
{
switch (poly_modulus_degree)
{
case std::size_t(1024):
return 25;
case std::size_t(2048):
return 51;
case std::size_t(4096):
return 101;
case std::size_t(8192):
return 202;
case std::size_t(16384):
return 411;
case std::size_t(32768):
return 827;
}
return 0;
}
// Ternary secret; 192 bits quantum security
SEAL_NODISCARD constexpr int seal_he_std_parms_192_tq(std::size_t poly_modulus_degree) noexcept
{
switch (poly_modulus_degree)
{
case std::size_t(1024):
return 17;
case std::size_t(2048):
return 35;
case std::size_t(4096):
return 70;
case std::size_t(8192):
return 141;
case std::size_t(16384):
return 284;
case std::size_t(32768):
return 571;
}
return 0;
}
// Ternary secret; 256 bits quantum security
SEAL_NODISCARD constexpr int seal_he_std_parms_256_tq(std::size_t poly_modulus_degree) noexcept
{
switch (poly_modulus_degree)
{
case std::size_t(1024):
return 13;
case std::size_t(2048):
return 27;
case std::size_t(4096):
return 54;
case std::size_t(8192):
return 109;
case std::size_t(16384):
return 220;
case std::size_t(32768):
return 443;
}
return 0;
}
// Standard deviation for error distribution
constexpr double seal_he_std_parms_error_std_dev = 3.2;
} // namespace util
} // namespace seal