summaryrefslogtreecommitdiff
path: root/lib/mpi/mpi-mpow.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/mpi/mpi-mpow.c')
-rw-r--r--lib/mpi/mpi-mpow.c134
1 files changed, 0 insertions, 134 deletions
diff --git a/lib/mpi/mpi-mpow.c b/lib/mpi/mpi-mpow.c
deleted file mode 100644
index 7328d0d..0000000
--- a/lib/mpi/mpi-mpow.c
+++ /dev/null
@@ -1,134 +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 "mpi-internal.h"
-#include "longlong.h"
-
-static int build_index(const 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
- */
-int mpi_mulpowm(MPI res, MPI *basearray, MPI *exparray, MPI m)
-{
- int rc = -ENOMEM;
- int k; /* number of elements */
- int t; /* bit size of largest exponent */
- int i, j, idx;
- MPI *G = NULL; /* table with precomputed values of size 2^k */
- MPI tmp = NULL;
-
- for (k = 0; basearray[k]; k++)
- ;
- if (!k) {
- pr_emerg("mpi_mulpowm: assert(k) failed\n");
- BUG();
- }
- for (t = 0, i = 0; (tmp = exparray[i]); i++) {
- j = mpi_get_nbits(tmp);
- if (j > t)
- t = j;
- }
- if (i != k) {
- pr_emerg("mpi_mulpowm: assert(i==k) failed\n");
- BUG();
- }
- if (!t) {
- pr_emerg("mpi_mulpowm: assert(t) failed\n");
- BUG();
- }
- if (k >= 10) {
- pr_emerg("mpi_mulpowm: assert(k<10) failed\n");
- BUG();
- }
-
- G = kzalloc((1 << k) * sizeof *G, GFP_KERNEL);
- if (!G)
- goto err_out;
-
- /* and calculate */
- tmp = mpi_alloc(mpi_get_nlimbs(m) + 1);
- if (!tmp)
- goto nomem;
- if (mpi_set_ui(res, 1) < 0)
- goto nomem;
- for (i = 1; i <= t; i++) {
- if (mpi_mulm(tmp, res, res, m) < 0)
- goto nomem;
- idx = build_index(exparray, k, i, t);
- if (!(idx >= 0 && idx < (1 << k))) {
- pr_emerg("mpi_mulpowm: assert(idx >= 0 && idx < (1<<k)) failed\n");
- BUG();
- }
- if (!G[idx]) {
- if (!idx) {
- G[0] = mpi_alloc_set_ui(1);
- if (!G[0])
- goto nomem;
- } else {
- for (j = 0; j < k; j++) {
- if ((idx & (1 << j))) {
- if (!G[idx]) {
- if (mpi_copy
- (&G[idx],
- basearray[j]) < 0)
- goto nomem;
- } else {
- if (mpi_mulm
- (G[idx], G[idx],
- basearray[j],
- m) < 0)
- goto nomem;
- }
- }
- }
- if (!G[idx]) {
- G[idx] = mpi_alloc(0);
- if (!G[idx])
- goto nomem;
- }
- }
- }
- if (mpi_mulm(res, tmp, G[idx], m) < 0)
- goto nomem;
- }
-
- rc = 0;
-nomem:
- /* cleanup */
- mpi_free(tmp);
- for (i = 0; i < (1 << k); i++)
- mpi_free(G[i]);
- kfree(G);
-err_out:
- return rc;
-}