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/*
* Created on 08/04/2005
*
* 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 com.fasteasytrade.jrandtest.io.FileAlgoRandomStream;
/**
* SHA1 algorithm as a random stream based on SHA1 message digest class.
*
* Implementation is based on SHA1 algorithm in NIST test package.
*
*
* @author Zur Aougav
*/
public class SHA1Random extends FileAlgoRandomStream {
SHA1 algo = null;
/**
* outAlgoBuffer is filled with key array, the first time. The buffer is
* used as an input and output to SHA1.
*/
byte[] outAlgoBuffer = new byte[20];
int outAlgoBufferIx = outAlgoBuffer.length;
/**
* random IV to SHA1 class
*/
byte[] iv = new byte[20];
/**
* random Key to SHA1 class. Used as the first update input buffer to SHA1
* (key is copied into outAlgoBuffer).
*/
byte[] key = new byte[20];
public SHA1Random() {
super();
}
public SHA1Random(String keyFileName) {
super(keyFileName);
}
@Override
public void setupKeys() {
super.setupKeys();
}
@Override
public void setup() {
/**
* makes only once a new SHA1 object and an IV vector.
*/
if (algo == null) {
algo = new SHA1();
java.util.Random rnd = new java.util.Random(new java.util.Date().getTime());
rnd.nextBytes(iv);
rnd.nextBytes(key);
}
/**
* First time, the key array is the input to SHA1, so we copy it into
* outAlgoBuffer (which is used as input and outut buffer to SHA1).
*/
System.arraycopy(key, 0, outAlgoBuffer, 0, outAlgoBuffer.length);
}
@Override
public boolean openInputStream() {
if (filename != null) {
super.openInputStream();
}
setup(); // make sure algorithm and keys/states are reset
count = 0;
countLastRead = SIZE;
actualSize = SIZE;
outAlgoBufferIx = outAlgoBuffer.length;
open = true;
return open;
}
@Override
public byte readByte() {
if (!isOpen()) {
return -1;
}
if (filename == null && count > maxCount) {
open = false;
return -1;
}
if (outAlgoBufferIx == outAlgoBuffer.length) {
algo.init(iv);
/**
* update SHA1 using outAlgoBuffer array (20 bytes = 160 bits) 4
* times, so update with 80 bytes ( > 64 bytes = 512 bits!)
*/
for (int k = 0; k < 4; k++) {
algo.update(outAlgoBuffer);
}
/**
* gets H internal vector from SHA1 as output buffer (and as input
* to next update iteration).
*/
algo.getHAsBytes(outAlgoBuffer);
outAlgoBufferIx = 0;
}
byte prng = outAlgoBuffer[outAlgoBufferIx++];
if (filename == null) {
count++;
return prng;
}
/*
* we have a real filename to encrypt
*/
byte data = super.readByte();
return (byte)(prng ^ data);
}
@Override
public int readInt() {
if (!isOpen()) {
return -1;
}
if (filename == null && count > maxCount) {
open = false;
return -1;
}
int prng = 0xff & readByte();
prng = (prng << 8) | (0xff & readByte());
prng = (prng << 8) | (0xff & readByte());
prng = (prng << 8) | (0xff & readByte());
return prng;
}
@Override
public long readLong() {
if (!isOpen()) {
return -1;
}
if (filename == null && count > maxCount) {
open = false;
return -1;
}
long prng = 0xff & readByte();
for (int i = 0; i < 7; i++) {
prng = (prng << 8) | (0xff & readByte());
}
return prng;
}
public static void main(String[] args) {
if (args != null && args.length > 0 && args[0] != null) {
SHA1Random algo = new SHA1Random();
algo.setup();
try {
algo.openInputStream();
for (int i = 0; i < 100; i++) {
System.out.print(algo.readByte());
System.out.print(",");
}
System.out.println();
} catch (Exception e) {
System.out.println("" + e);
}
}
}
}