
This algorithm allows for much faster computations of modular powers (around a 5x-10x speedup of the Crypto test). However, it is only valid for odd modulo values, and therefore the old algorithm must be kept for computations involving even modulo values.
40 lines
4.4 KiB
C++
40 lines
4.4 KiB
C++
/*
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* Copyright (c) 2021, Dex♪ <dexes.ttp@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <LibCrypto/BigInt/UnsignedBigInteger.h>
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namespace Crypto {
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class UnsignedBigIntegerAlgorithms {
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public:
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static void add_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
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static void add_into_accumulator_without_allocation(UnsignedBigInteger& accumulator, UnsignedBigInteger const& value);
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static void subtract_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
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static void bitwise_or_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
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static void bitwise_and_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
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static void bitwise_xor_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
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static void bitwise_not_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger& output);
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static void shift_left_without_allocation(UnsignedBigInteger const& number, size_t bits_to_shift_by, UnsignedBigInteger& temp_result, UnsignedBigInteger& temp_plus, UnsignedBigInteger& output);
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static void multiply_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& temp_shift_result, UnsignedBigInteger& temp_shift_plus, UnsignedBigInteger& temp_shift, UnsignedBigInteger& output);
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static void divide_without_allocation(UnsignedBigInteger const& numerator, UnsignedBigInteger const& denominator, UnsignedBigInteger& temp_shift_result, UnsignedBigInteger& temp_shift_plus, UnsignedBigInteger& temp_shift, UnsignedBigInteger& temp_minus, UnsignedBigInteger& quotient, UnsignedBigInteger& remainder);
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static void divide_u16_without_allocation(UnsignedBigInteger const& numerator, UnsignedBigInteger::Word denominator, UnsignedBigInteger& quotient, UnsignedBigInteger& remainder);
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static void destructive_GCD_without_allocation(UnsignedBigInteger& temp_a, UnsignedBigInteger& temp_b, UnsignedBigInteger& temp_1, UnsignedBigInteger& temp_2, UnsignedBigInteger& temp_3, UnsignedBigInteger& temp_4, UnsignedBigInteger& temp_quotient, UnsignedBigInteger& temp_remainder, UnsignedBigInteger& output);
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static void modular_inverse_without_allocation(UnsignedBigInteger const& a_, UnsignedBigInteger const& b, UnsignedBigInteger& temp_1, UnsignedBigInteger& temp_2, UnsignedBigInteger& temp_3, UnsignedBigInteger& temp_4, UnsignedBigInteger& temp_minus, UnsignedBigInteger& temp_quotient, UnsignedBigInteger& temp_d, UnsignedBigInteger& temp_u, UnsignedBigInteger& temp_v, UnsignedBigInteger& temp_x, UnsignedBigInteger& result);
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static void destructive_modular_power_without_allocation(UnsignedBigInteger& ep, UnsignedBigInteger& base, UnsignedBigInteger const& m, UnsignedBigInteger& temp_1, UnsignedBigInteger& temp_2, UnsignedBigInteger& temp_3, UnsignedBigInteger& temp_4, UnsignedBigInteger& temp_multiply, UnsignedBigInteger& temp_quotient, UnsignedBigInteger& temp_remainder, UnsignedBigInteger& result);
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static void montgomery_modular_power_with_minimal_allocations(UnsignedBigInteger const& base, UnsignedBigInteger const& exponent, UnsignedBigInteger const& modulo, UnsignedBigInteger& temp_z0, UnsignedBigInteger& temp_rr, UnsignedBigInteger& temp_one, UnsignedBigInteger& temp_z, UnsignedBigInteger& temp_zz, UnsignedBigInteger& temp_x, UnsignedBigInteger& temp_extra, UnsignedBigInteger& result);
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private:
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static UnsignedBigInteger::Word montgomery_fragment(UnsignedBigInteger& z, size_t offset_in_z, UnsignedBigInteger const& x, UnsignedBigInteger::Word y_digit, size_t num_words);
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static void almost_montgomery_multiplication_without_allocation(UnsignedBigInteger const& x, UnsignedBigInteger const& y, UnsignedBigInteger const& modulo, UnsignedBigInteger& z, UnsignedBigInteger::Word k, size_t num_words, UnsignedBigInteger& result);
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static void shift_left_by_n_words(UnsignedBigInteger const& number, size_t number_of_words, UnsignedBigInteger& output);
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static void shift_right_by_n_words(UnsignedBigInteger const& number, size_t number_of_words, UnsignedBigInteger& output);
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ALWAYS_INLINE static UnsignedBigInteger::Word shift_left_get_one_word(UnsignedBigInteger const& number, size_t num_bits, size_t result_word_index);
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};
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}
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