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1: /* ARCFourRandomSpi.java -- 2: Copyright (C) 2002, 2003, 2006 Free Software Foundation, Inc. 3: 4: This file is a part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2 of the License, or (at 9: your option) any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; if not, write to the Free Software 18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 19: USA 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package gnu.javax.crypto.jce.prng; 40: 41: import gnu.java.security.Registry; 42: import gnu.javax.crypto.prng.ARCFour; 43: import gnu.java.security.prng.IRandom; 44: import gnu.java.security.prng.LimitReachedException; 45: import gnu.javax.crypto.prng.PRNGFactory; 46: 47: import java.security.SecureRandomSpi; 48: import java.util.HashMap; 49: 50: /** 51: * Implementation of the <i>Service Provider Interface</i> (<b>SPI</b>) for 52: * the ARCFOUR keystream generator. 53: */ 54: public class ARCFourRandomSpi 55: extends SecureRandomSpi 56: { 57: /** Our underlying prng instance. */ 58: private IRandom adaptee; 59: /** Have we been initialized? */ 60: private boolean virgin; 61: 62: /** 63: * Default 0-arguments constructor. 64: */ 65: public ARCFourRandomSpi() 66: { 67: super(); 68: adaptee = PRNGFactory.getInstance(Registry.ARCFOUR_PRNG); 69: virgin = true; 70: } 71: 72: public byte[] engineGenerateSeed(int numBytes) 73: { 74: if (numBytes < 1) 75: return new byte[0]; 76: byte[] result = new byte[numBytes]; 77: this.engineNextBytes(result); 78: return result; 79: } 80: 81: public void engineNextBytes(byte[] bytes) 82: { 83: if (virgin) 84: this.engineSetSeed(new byte[0]); 85: try 86: { 87: adaptee.nextBytes(bytes, 0, bytes.length); 88: } 89: catch (LimitReachedException ignored) 90: { 91: } 92: } 93: 94: public void engineSetSeed(byte[] seed) 95: { 96: HashMap attributes = new HashMap(); 97: attributes.put(ARCFour.ARCFOUR_KEY_MATERIAL, seed); 98: adaptee.init(attributes); 99: virgin = false; 100: } 101: }