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/*
* Created on 17/02/2005
*
* JRandTest package
*
* Copyright (c) 2005, Zur Aougav, [email protected]
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this list
* of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* Neither the name of the JRandTest nor the names of its contributors may be
* used to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.fasteasytrade.jrandtest.algo;
import java.io.FileOutputStream;
import java.io.PrintStream;
/**
* Alleged RC4 implemented as RC4Key. Returns byte.
*
* Include debug level and logging into external file.
*
* @author Zur Aougav
*
*/
public class RC4Key extends Cipher {
boolean ready = false; // is the algorithm is ready?
private byte[] Key; // original key
private byte[] KeyBytes = new byte[256];
private byte[] CypherBytes = new byte[256];
int i, jump;
PrintStream ps = null; // used by the log
int debugLevel = 0; // write to log : 0=none, 1=stream, 2=full dscription
/**
* @param Key
* is a byte array to init internal state vector.
* @param d
* for debug level. 0 is none. 1 is minimal into logfile. 2 is
* detailed.
* @param logname
* is used with d > 0
*/
RC4Key(byte[] Key, int d, String logname) {
debugLevel = d;
try {
if (debugLevel > 0) {
ps = new PrintStream(new FileOutputStream(getClass().getName() + logname + ".log"));
}
} catch (Exception e) {
System.out.println(e);
ps = null;
}
if (Key.length == 0) {
return;
}
this.Key = Key;
for (i = 0; i < 256; ++i) {
KeyBytes[i] = Key[i % Key.length];
}
for (i = 0; i < 256; ++i) {
CypherBytes[i] = (byte)i;
}
jump = 0;
byte temp;
for (i = 0; i < 256; ++i) {
jump = (0xFF & jump + 0xFF & CypherBytes[i] + 0xFF & KeyBytes[i]) & 0xFF;
temp = CypherBytes[i];
CypherBytes[i] = CypherBytes[jump];
CypherBytes[jump] = temp;
}
i = 0;
jump = 0;
ready = true;
}
/**
* encrypt/decrypt from data to Result. Uses the key in Key
*/
public byte next() {
if (!ready) {
return (byte)0x00;
}
i = (i + 1) % 256;
if (debugLevel == 2) {
print("i=" + i + ", j=" + jump + " +c[" + i + "]=");
print(CypherBytes[i]);
}
jump = ((0xFF & jump) + (0xFF & CypherBytes[i])) & 0xff; // % 256;
if (debugLevel == 2) {
print(", new j=" + jump + ", c[j]=");
print(CypherBytes[jump]);
print(", c[i]=");
print(CypherBytes[i]);
print(" + c[j]=");
print(CypherBytes[jump]);
}
int T = ((0xFF & CypherBytes[i]) + (0xFF & CypherBytes[jump])) & 0xff;
if (debugLevel == 2) {
print(" ==> T=" + T);
}
byte temp = CypherBytes[i];
CypherBytes[i] = CypherBytes[jump];
CypherBytes[jump] = temp;
if (debugLevel == 2) {
print(" returns c[t]=");
println(CypherBytes[T]);
}
if (debugLevel == 1 && ps != null) {
ps.print(CypherBytes[T]);
}
return CypherBytes[T];
}
public void print(String s) {
if (ps == null) {
return;
}
ps.print(s);
}
public void println(String s) {
if (ps == null) {
return;
}
ps.println(s);
}
public void print(byte s) {
if (ps == null) {
return;
}
ps.print(0xff & s);
}
public void println(byte s) {
if (ps == null) {
return;
}
ps.println(0xff & s);
}
/**
* carefull clear of buffers in RC4Key object
*
*/
@Override
protected void finalize() throws Throwable {
super.finalize();
System.out.println("RC4Key finalize...");
if (Key != null) {
java.util.Arrays.fill(Key, 0, Key.length, (byte)0x00);
}
java.util.Arrays.fill(KeyBytes, 0, KeyBytes.length, (byte)0x00);
java.util.Arrays.fill(CypherBytes, 0, CypherBytes.length, (byte)0x00);
Key = null;
KeyBytes = null;
CypherBytes = null;
}
}