116 lines
2.2 KiB
C
116 lines
2.2 KiB
C
/*
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* Copyright (C) 2014-2016 Andreas Steffen
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* HSR Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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/**
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* @defgroup ntt_fft_params ntt_fft_params
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* @{ @ingroup ntt_p
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*/
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#ifndef NTT_FFT_PARAMS_H_
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#define NTT_FFT_PARAMS_H_
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#include <library.h>
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typedef struct ntt_fft_params_t ntt_fft_params_t;
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/**
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* Defines the parameters for an NTT computed via the FFT algorithm
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*/
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struct ntt_fft_params_t {
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/**
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* Prime modulus
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*/
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uint16_t q;
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/**
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* Inverse of Prime modulus (-q_inv * q mod r = 1)
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*/
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uint16_t q_inv;
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/**
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* Logarithm of Montgomery radix: log2(r)
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*/
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uint16_t rlog;
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/**
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* Square of Montgomery radix: r^2 mod q
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*/
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const uint32_t r2;
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/**
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* Montgomery radix mask: (1<<rlog) - 1
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*/
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const uint32_t rmask;
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/**
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* Size of the FFT with the condition k * n = q-1
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*/
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const uint16_t n;
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/**
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* Inverse of n mod q used for normalization of the FFT
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*/
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const uint16_t n_inv;
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/**
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* Number of FFT stages stages = log2(n)
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*/
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const uint16_t stages;
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/**
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* FFT twiddle factors (n-th roots of unity) in Montgomery form
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*/
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const uint16_t *wr;
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/**
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* FFT phase shift (2n-th roots of unity) in forward transform
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*/
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const uint16_t *wf;
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/**
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* FFT phase shift (2n-th roots of unity) and scaling in inverse transform
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*/
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const uint16_t *wi;
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/**
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* Subsampling of FFT twiddle factors table
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*/
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const uint16_t s;
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/**
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* FFT bit reversal
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*/
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const uint16_t *rev;
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};
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/**
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* FFT parameters for q = 12289 and n = 1024
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*/
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extern const ntt_fft_params_t ntt_fft_12289_1024;
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/**
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* FFT parameters for q = 12289 and n = 512
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*/
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extern const ntt_fft_params_t ntt_fft_12289_512;
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/**
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* FFT parameters for q = 17 and n = 8
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*/
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extern const ntt_fft_params_t ntt_fft_17_8;
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#endif /** NTT_FFT_PARAMS_H_ @}*/
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