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