1 /* 2 * Copyright (c) 1998, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* @test 25 * @bug 4181191 26 * @summary test BigInteger modPow method 27 */ 28 import java.math.BigInteger; 29 import java.util.Random; 30 31 public class ModPow { 32 public static void main(String[] args) { 33 Random rnd = new Random(1234); 34 35 for (int i=0; i<2000; i++) { 36 BigInteger m = new BigInteger(800, rnd); 37 BigInteger base = new BigInteger(16, rnd); 38 if (rnd.nextInt() % 1 == 0) 39 base = base.negate(); 40 BigInteger exp = new BigInteger(8, rnd); 41 42 BigInteger z = base.modPow(exp, m); 43 BigInteger w = base.pow(exp.intValue()).mod(m); 44 if (!z.equals(w)){ 45 System.err.println(base +" ** " + exp + " mod "+ m); 46 System.err.println("modPow : " + z); 47 System.err.println("pow.mod: " + w); 48 throw new RuntimeException("BigInteger modPow failure."); 49 } 50 } 51 } 52 }