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Diffstat (limited to 'mpi/mpi-mpow.c')
-rw-r--r-- | mpi/mpi-mpow.c | 101 |
1 files changed, 0 insertions, 101 deletions
diff --git a/mpi/mpi-mpow.c b/mpi/mpi-mpow.c deleted file mode 100644 index 7c46fc65c..000000000 --- a/mpi/mpi-mpow.c +++ /dev/null @@ -1,101 +0,0 @@ -/* mpi-mpow.c - MPI functions - * Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc. - * - * This file is part of GnuPG. - * - * GnuPG 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. - * - * GnuPG 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. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA - */ - -#include <config.h> -#include <stdio.h> -#include <stdlib.h> -#include "mpi-internal.h" -#include "longlong.h" -#include <assert.h> - -static int -build_index( MPI *exparray, int k, int i, int t ) -{ - int j, bitno; - int index = 0; - - bitno = t-i; - for(j=k-1; j >= 0; j-- ) { - index <<= 1; - if( mpi_test_bit( exparray[j], bitno ) ) - index |= 1; - } - return index; -} - -/**************** - * RES = (BASE[0] ^ EXP[0]) * (BASE[1] ^ EXP[1]) * ... * mod M - */ -void -mpi_mulpowm( MPI res, MPI *basearray, MPI *exparray, MPI m) -{ - int k; /* number of elements */ - int t; /* bit size of largest exponent */ - int i, j, idx; - MPI *G; /* table with precomputed values of size 2^k */ - MPI tmp; - - for(k=0; basearray[k]; k++ ) - ; - assert(k); - for(t=0, i=0; (tmp=exparray[i]); i++ ) { - j = mpi_get_nbits(tmp); - if( j > t ) - t = j; - } - assert(i==k); - assert(t); - assert( k < 10 ); - - G = m_alloc_clear( (1<<k) * sizeof *G ); - /* and calculate */ - tmp = mpi_alloc( mpi_get_nlimbs(m)+1 ); - mpi_set_ui( res, 1 ); - for(i = 1; i <= t; i++ ) { - mpi_mulm(tmp, res, res, m ); - idx = build_index( exparray, k, i, t ); - assert( idx >= 0 && idx < (1<<k) ); - if( !G[idx] ) { - if( !idx ) - G[0] = mpi_alloc_set_ui( 1 ); - else { - for(j=0; j < k; j++ ) { - if( (idx & (1<<j) ) ) { - if( !G[idx] ) - G[idx] = mpi_copy( basearray[j] ); - else - mpi_mulm( G[idx], G[idx], basearray[j], m ); - } - } - if( !G[idx] ) - G[idx] = mpi_alloc(0); - } - } - mpi_mulm(res, tmp, G[idx], m ); - } - - /* cleanup */ - mpi_free(tmp); - for(i=0; i < (1<<k); i++ ) - mpi_free(G[i]); - m_free(G); -} - - |