16e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)// Copyright 2014 The Chromium Authors. All rights reserved. 26e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 36e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)// found in the LICENSE file. 46e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) 56e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)package org.chromium.chromoting; 66e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) 76e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)import java.io.FileInputStream; 86e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)import java.io.IOException; 96e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)import java.security.SecureRandom; 106e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) 116e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)/** 126e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) * This class contains code to initialize a SecureRandom generator securely on Android platforms 136e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) * <= 4.3. See 146e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) * {@link http://android-developers.blogspot.com/2013/08/some-securerandom-thoughts.html}. 156e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) */ 166e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)public class SecureRandomInitializer { 176e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) private static final int NUM_RANDOM_BYTES = 16; 186e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) 196e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) /** 206e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) * Safely initializes the random number generator, by seeding it with data from /dev/urandom. 216e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) */ 226e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) public static void initialize(SecureRandom generator) throws IOException { 236e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) FileInputStream fis = null; 246e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) try { 256e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) fis = new FileInputStream("/dev/urandom"); 266e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) byte[] bytes = new byte[NUM_RANDOM_BYTES]; 276e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) if (bytes.length != fis.read(bytes)) { 286e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) throw new IOException("Failed to get enough random data."); 296e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) } 306e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) generator.setSeed(bytes); 316e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) } finally { 326e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) try { 336e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) if (fis != null) { 346e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) fis.close(); 356e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) } 366e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) } catch (IOException e) { 376e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) // Ignore exception closing the device. 386e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) } 396e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) } 406e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles) } 416e8cce623b6e4fe0c9e4af605d675dd9d0338c38Torne (Richard Coles)} 42