1 files changed, 61 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/mpi/utils/invmod.c b/security/nss/lib/freebl/mpi/utils/invmod.c
new file mode 100644
index 000000000..9b4b04d3f
--- /dev/null
+++ b/security/nss/lib/freebl/mpi/utils/invmod.c
@@ -0,0 +1,61 @@
+/*
+ *  invmod.c
+ *
+ *  Compute modular inverses
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "mpi.h"
+
+int
+main(int argc, char *argv[])
+{
+    mp_int a, m;
+    mp_err res;
+    char *buf;
+    int len, out = 0;
+
+    if (argc < 3) {
+        fprintf(stderr, "Usage: %s <a> <m>\n", argv[0]);
+        return 1;
+    }
+
+    mp_init(&a);
+    mp_init(&m);
+    mp_read_radix(&a, argv[1], 10);
+    mp_read_radix(&m, argv[2], 10);
+
+    if (mp_cmp(&a, &m) > 0)
+        mp_mod(&a, &m, &a);
+
+    switch ((res = mp_invmod(&a, &m, &a))) {
+        case MP_OKAY:
+            len = mp_radix_size(&a, 10);
+            buf = malloc(len);
+
+            mp_toradix(&a, buf, 10);
+            printf("%s\n", buf);
+            free(buf);
+            break;
+
+        case MP_UNDEF:
+            printf("No inverse\n");
+            out = 1;
+            break;
+
+        default:
+            printf("error: %s (%d)\n", mp_strerror(res), res);
+            out = 2;
+            break;
+    }
+
+    mp_clear(&a);
+    mp_clear(&m);
+
+    return out;
+}