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      1 /*
      2  * Copyright (C) 2009 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package tests.security;
     17 
     18 import java.security.NoSuchAlgorithmException;
     19 import java.security.SecureRandom;
     20 import java.util.Arrays;
     21 import java.util.concurrent.Callable;
     22 import java.util.concurrent.ExecutorCompletionService;
     23 import java.util.concurrent.ExecutorService;
     24 import java.util.concurrent.Executors;
     25 import junit.framework.TestCase;
     26 
     27 public abstract class SecureRandomTest extends TestCase {
     28 
     29     private final String algorithmName;
     30 
     31     private int counter = 0;
     32 
     33     protected SecureRandomTest(String name) {
     34         this.algorithmName = name;
     35     }
     36 
     37     protected void setUp() throws Exception {
     38         super.setUp();
     39     }
     40 
     41     public void testSecureRandom() {
     42         SecureRandom secureRandom1 = null;
     43         try {
     44             secureRandom1 = SecureRandom.getInstance(algorithmName);
     45         } catch (NoSuchAlgorithmException e) {
     46             fail(e.getMessage());
     47         }
     48 
     49         SecureRandom secureRandom2 = null;
     50         try {
     51             secureRandom2 = SecureRandom.getInstance(algorithmName);
     52         } catch (NoSuchAlgorithmException e) {
     53             fail(e.getMessage());
     54         }
     55 
     56         byte[] testRandom1 = getRandomBytes(secureRandom1);
     57         byte[] testRandom2 = getRandomBytes(secureRandom2);
     58 
     59         assertFalse(Arrays.equals(testRandom1, testRandom2));
     60 
     61 
     62     }
     63 
     64     private byte[] getRandomBytes(SecureRandom random) {
     65         byte[] randomData = new byte[64];
     66 
     67         random.setSeed(System.currentTimeMillis()+counter);
     68         counter++;
     69 
     70         random.nextBytes(randomData);
     71 
     72         return randomData;
     73     }
     74 
     75 
     76     public void testSecureRandomThreadSafety() throws Exception {
     77         final SecureRandom secureRandom = SecureRandom.getInstance(algorithmName);
     78         int threads = 2;
     79         ExecutorService executor = Executors.newFixedThreadPool(threads);
     80         ExecutorCompletionService ecs = new ExecutorCompletionService(executor);
     81         for (int t = 0; t < threads; t++) {
     82             ecs.submit(new Callable<Void>() {
     83                 public Void call () {
     84                     for (int i = 0; i < 1000; i++) {
     85                         secureRandom.generateSeed(1024);
     86                     }
     87                     return null;
     88                 }
     89             });
     90         }
     91         executor.shutdown();
     92         for (int i = 0; i < threads; i++) {
     93             ecs.take().get();
     94         }
     95     }
     96 }
     97