00001 // Cipher - an encryption template 00002 // 00003 // Copyright (C) 1996 by Jef Poskanzer <jef@acme.com>. All rights reserved. 00004 // 00005 // Redistribution and use in source and binary forms, with or without 00006 // modification, are permitted provided that the following conditions 00007 // are met: 00008 // 1. Redistributions of source code must retain the above copyright 00009 // notice, this list of conditions and the following disclaimer. 00010 // 2. Redistributions in binary form must reproduce the above copyright 00011 // notice, this list of conditions and the following disclaimer in the 00012 // documentation and/or other materials provided with the distribution. 00013 // 00014 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 00015 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 00016 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 00017 // ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 00018 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 00019 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 00020 // OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 00021 // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00022 // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 00023 // OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00024 // SUCH DAMAGE. 00025 // 00026 // Visit the ACME Labs Java page for up-to-date versions of this and other 00027 // fine Java utilities: http://www.acme.com/java/ 00028 00029 package Acme.Crypto; 00030 00031 import java.io.*; 00032 00034 // <P> 00035 // <A HREF="/resources/classes/Acme/Crypto/Cipher.java">Fetch the software.</A><BR> 00036 // <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A> 00037 // <P> 00038 // @see StreamCipher 00039 // @see BlockCipher 00040 // @see EncryptedOutputStream 00041 // @see EncryptedInputStream 00042 00043 public abstract class Cipher extends CryptoUtils 00044 { 00045 00047 public Cipher( int keySize ) 00048 { 00049 this.keySize = keySize; 00050 } 00051 00053 // also use 0. 00054 public int keySize; 00055 00057 public int keySize() 00058 { 00059 return keySize; 00060 } 00061 00063 public abstract void setKey( byte[] key ); 00064 00065 00066 // Utility routines. 00067 00069 public void setKey( String keyStr ) 00070 { 00071 setKey( makeKey( keyStr ) ); 00072 } 00073 00075 public byte[] makeKey( String keyStr ) 00076 { 00077 byte[] key; 00078 if ( keySize == 0 ) 00079 key = new byte[keyStr.length()]; 00080 else 00081 key = new byte[keySize]; 00082 int i, j; 00083 00084 for ( j = 0; j < key.length; ++j ) 00085 key[j] = 0; 00086 00087 for ( i = 0, j = 0; i < keyStr.length(); ++i, j = (j+1) % key.length ) 00088 key[j] ^= (byte) keyStr.charAt( i ); 00089 00090 return key; 00091 } 00092 00093 }