1 /* 2 * Copyright (c) 2013, 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 /** 25 * @test 26 * @bug 6425477 27 * @summary Better support for generation of high entropy random numbers 28 * @run main/othervm StrongSeedReader 29 */ 30 31 import java.io.*; 32 import java.net.*; 33 import java.security.SecureRandom; 34 35 /** 36 * A simple test which takes into account knowledge about the underlying 37 * implementation. This may change if the implementations change. 38 * 39 * Create a new EGD file with known bytes, then set the EGD System property. The 40 * data read should be the same as what was written. 41 */ 42 public class StrongSeedReader { 43 44 public static void main(String[] args) throws Exception { 45 // Skip Windows, the SHA1PRNG uses CryptGenRandom. 46 if (System.getProperty("os.name", "unknown").startsWith("Windows")) { 47 return; 48 } 49 50 File file = null; 51 try { 52 file = new File(System.getProperty("java.io.tmpdir"), 53 "StrongSeedReader.tmpdata"); 54 55 // write a bunch of 0's to the file. 56 FileOutputStream fos = new FileOutputStream(file); 57 fos.write(new byte[2048]); 58 59 System.setProperty("java.security.egd", file.toURI().toString()); 60 testSeed("NativePRNG"); 61 testSeed("SHA1PRNG"); 62 testSeed("DRBG"); 63 } finally { 64 if (file != null) { 65 file.delete(); 66 } 67 } 68 } 69 70 private static void testSeed(String alg) throws Exception { 71 System.out.println("Testing: " + alg); 72 SecureRandom sr = SecureRandom.getInstance(alg); 73 byte[] ba = sr.generateSeed(20); 74 75 // We should get back a bunch of zeros from the file. 76 for (byte b : ba) { 77 if (b != 0) { 78 throw new Exception("Byte != 0"); 79 } 80 } 81 } 82 }