136 lines
4.2 KiB
C
136 lines
4.2 KiB
C
/**
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* @file pstmnt.c
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* @version $Format:%h%d$
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*
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* Multiprecision number implementation: constant time montgomery.
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*/
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/*
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* Copyright (c) 2013-2017 INSIDE Secure Corporation
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* Copyright (c) PeerSec Networks, 2002-2011
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* All Rights Reserved
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*
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* The latest version of this code is available at http://www.matrixssl.org
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*
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* This software is open source; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This General Public License does NOT permit incorporating this software
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* into proprietary programs. If you are unable to comply with the GPL, a
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* commercial license for this software may be purchased from INSIDE at
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* http://www.insidesecure.com/
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*
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* This program is distributed in WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* http://www.gnu.org/copyleft/gpl.html
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*/
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/******************************************************************************/
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#ifndef INCLUDE_GUARD_PSTMNT_H
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# define INCLUDE_GUARD_PSTMNT_H
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# include "../cryptoApi.h"
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# include "pstm.h"
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/* Before defining pstmnt, ensure pstm has been processed.
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In some configurations the pstm is disabled,
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which also disables pstmnt. */
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# ifndef PSTM_AVAILABLE
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# undef USE_CONSTANT_TIME_MODEXP
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# endif /* PSTM_AVAILABLE */
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# ifdef USE_CONSTANT_TIME_MODEXP
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/* pstmnt uses data types subtly different from pstm:
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all limbs specified in the API are always multiples of uint32_t. */
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# define pstmnt_bits uint32_t
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# define pstmnt_word uint32_t
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# define pstmnt_words uint32_t
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# define pstmnt_dword uint64_t
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# define PSTMNT_WORD_BITS 32
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# define PSTMNT_WORD_BYTES 4
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/* Inline functions for conversion between types. */
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static inline
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const pstmnt_word *pstmnt_const_ptr(const pstm_int *A_const)
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{
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return (const pstmnt_word *) A_const->dp;
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}
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static inline
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pstmnt_word *pstmnt_ptr(pstm_int *A)
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{
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return (pstmnt_word *) A->dp;
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}
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static inline
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pstmnt_words pstmnt_size(const pstm_int *A)
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{
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return ((A->used) * DIGIT_BIT) / PSTMNT_WORD_BITS;
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}
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static inline
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unsigned int pstmnt_size_bytes(const pstm_int *A)
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{
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return ((A->used) * DIGIT_BIT) / 8;
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}
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/* Function attributes. */
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# define PSTMNT_RESTORED /* Parameter is temporary changed during function call,
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but restored before the function returns. */
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/* Function API. */
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/* Compute small inverse constant for montgomery operations. */
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pstmnt_word pstmnt_neg_small_inv(const pstmnt_word *a_p);
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/* Convert values to montgomery format for processing modular exponentiation. */
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void
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pstmnt_montgomery_input(
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const pstmnt_word Input[] /* NWords */,
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PSTMNT_RESTORED pstmnt_word Prime[] /* NWords */,
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pstmnt_word TempLarge[] /* NWords * 6 */, /* Note: differs from
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pstmnt_montgomery_input. */
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pstmnt_word Target[] /* NWords */,
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pstmnt_words NWords,
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pstmnt_word PrimeSmallInv);
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/* Convert values back from montgomery format. */
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void
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pstmnt_montgomery_output(
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const pstmnt_word Input[] /* NWords */,
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pstmnt_word Output[] /* NWords */,
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const pstmnt_word Prime[] /* NWords */,
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pstmnt_word TempLarge[] /* NWords * 2 */,
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pstmnt_words NWords,
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pstmnt_word PrimeSmallInv);
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/* Compute modular exponentiation with values in montgomery format.
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The modular exponentiation attempts to use constant time amthematical
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operations. */
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void
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pstmnt_mod_exp_montgomery_skip(
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const pstmnt_word a[],
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const pstmnt_word x[],
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pstmnt_word r[],
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const pstmnt_word start_bit,
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const pstmnt_word bits,
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const pstmnt_word m[],
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pstmnt_word temp[] /* len * 4 */,
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pstmnt_word mp,
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pstmnt_words len);
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# endif /* INCLUDE_GUARD_PSTMNT_H */
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#endif /* USE_CONSTANT_TIME_MODEXP */
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/* end of file pstmnt.h */
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