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 }