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-rw-r--r--lib/mpi/mpi-inv.c187
1 files changed, 0 insertions, 187 deletions
diff --git a/lib/mpi/mpi-inv.c b/lib/mpi/mpi-inv.c
deleted file mode 100644
index 0951f98..0000000
--- a/lib/mpi/mpi-inv.c
+++ /dev/null
@@ -1,187 +0,0 @@
-/* mpi-inv.c - MPI functions
- * Copyright (C) 1998, 1999, 2000, 2001 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"
-
-/****************
- * Calculate the multiplicative inverse X of A mod N
- * That is: Find the solution x for
- * 1 = (a*x) mod n
- */
-int mpi_invm(MPI x, const MPI a, const MPI n)
-{
- /* Extended Euclid's algorithm (See TAOPC Vol II, 4.5.2, Alg X)
- * modified according to Michael Penk's solution for Exercice 35
- * with further enhancement */
- MPI u = NULL, v = NULL;
- MPI u1 = NULL, u2 = NULL, u3 = NULL;
- MPI v1 = NULL, v2 = NULL, v3 = NULL;
- MPI t1 = NULL, t2 = NULL, t3 = NULL;
- unsigned k;
- int sign;
- int odd = 0;
- int rc = -ENOMEM;
-
- if (mpi_copy(&u, a) < 0)
- goto cleanup;
- if (mpi_copy(&v, n) < 0)
- goto cleanup;
-
- for (k = 0; !mpi_test_bit(u, 0) && !mpi_test_bit(v, 0); k++) {
- if (mpi_rshift(u, u, 1) < 0)
- goto cleanup;
- if (mpi_rshift(v, v, 1) < 0)
- goto cleanup;
- }
- odd = mpi_test_bit(v, 0);
-
- u1 = mpi_alloc_set_ui(1);
- if (!u1)
- goto cleanup;
- if (!odd) {
- u2 = mpi_alloc_set_ui(0);
- if (!u2)
- goto cleanup;
- }
- if (mpi_copy(&u3, u) < 0)
- goto cleanup;
- if (mpi_copy(&v1, v) < 0)
- goto cleanup;
- if (!odd) {
- v2 = mpi_alloc(mpi_get_nlimbs(u));
- if (!v2)
- goto cleanup;
- if (mpi_sub(v2, u1, u) < 0)
- goto cleanup; /* U is used as const 1 */
- }
- if (mpi_copy(&v3, v) < 0)
- goto cleanup;
- if (mpi_test_bit(u, 0)) { /* u is odd */
- t1 = mpi_alloc_set_ui(0);
- if (!t1)
- goto cleanup;
- if (!odd) {
- t2 = mpi_alloc_set_ui(1);
- if (!t2)
- goto cleanup;
- t2->sign = 1;
- }
- if (mpi_copy(&t3, v) < 0)
- goto cleanup;
- t3->sign = !t3->sign;
- goto Y4;
- } else {
- t1 = mpi_alloc_set_ui(1);
- if (!t1)
- goto cleanup;
- if (!odd) {
- t2 = mpi_alloc_set_ui(0);
- if (!t2)
- goto cleanup;
- }
- if (mpi_copy(&t3, u) < 0)
- goto cleanup;
- }
- do {
- do {
- if (!odd) {
- if (mpi_test_bit(t1, 0) || mpi_test_bit(t2, 0)) { /* one is odd */
- if (mpi_add(t1, t1, v) < 0)
- goto cleanup;
- if (mpi_sub(t2, t2, u) < 0)
- goto cleanup;
- }
- if (mpi_rshift(t1, t1, 1) < 0)
- goto cleanup;
- if (mpi_rshift(t2, t2, 1) < 0)
- goto cleanup;
- if (mpi_rshift(t3, t3, 1) < 0)
- goto cleanup;
- } else {
- if (mpi_test_bit(t1, 0))
- if (mpi_add(t1, t1, v) < 0)
- goto cleanup;
- if (mpi_rshift(t1, t1, 1) < 0)
- goto cleanup;
- if (mpi_rshift(t3, t3, 1) < 0)
- goto cleanup;
- }
-Y4:
- ;
- } while (!mpi_test_bit(t3, 0)); /* while t3 is even */
-
- if (!t3->sign) {
- if (mpi_set(u1, t1) < 0)
- goto cleanup;
- if (!odd)
- if (mpi_set(u2, t2) < 0)
- goto cleanup;
- if (mpi_set(u3, t3) < 0)
- goto cleanup;
- } else {
- if (mpi_sub(v1, v, t1) < 0)
- goto cleanup;
- sign = u->sign;
- u->sign = !u->sign;
- if (!odd)
- if (mpi_sub(v2, u, t2) < 0)
- goto cleanup;
- u->sign = sign;
- sign = t3->sign;
- t3->sign = !t3->sign;
- if (mpi_set(v3, t3) < 0)
- goto cleanup;
- t3->sign = sign;
- }
- if (mpi_sub(t1, u1, v1) < 0)
- goto cleanup;
- if (!odd)
- if (mpi_sub(t2, u2, v2) < 0)
- goto cleanup;
- if (mpi_sub(t3, u3, v3) < 0)
- goto cleanup;
- if (t1->sign) {
- if (mpi_add(t1, t1, v) < 0)
- goto cleanup;
- if (!odd)
- if (mpi_sub(t2, t2, u) < 0)
- goto cleanup;
- }
- } while (mpi_cmp_ui(t3, 0)); /* while t3 != 0 */
- /* mpi_lshift( u3, k ); */
- rc = mpi_set(x, u1);
-
-cleanup:
- mpi_free(u1);
- mpi_free(v1);
- mpi_free(t1);
- if (!odd) {
- mpi_free(u2);
- mpi_free(v2);
- mpi_free(t2);
- }
- mpi_free(u3);
- mpi_free(v3);
- mpi_free(t3);
-
- mpi_free(u);
- mpi_free(v);
- return rc;
-}
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