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/*
* $Id: ARCFOUREncryption.java 3117 2008-01-31 05:53:22Z xlv $
*
* Copyright 2006 Paulo Soares
*
* The contents of this file are subject to the Mozilla Public License Version 1.1
* (the "License"); you may not use this file except in compliance with the License.
* You may obtain a copy of the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the License.
*
* The Original Code is 'iText, a free JAVA-PDF library'.
*
* The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
* the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
* All Rights Reserved.
* Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
* are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
*
* Contributor(s): all the names of the contributors are added in the source code
* where applicable.
*
* Alternatively, the contents of this file may be used under the terms of the
* LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
* provisions of LGPL are applicable instead of those above. If you wish to
* allow use of your version of this file only under the terms of the LGPL
* License and not to allow others to use your version of this file under
* the MPL, indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by the LGPL.
* If you do not delete the provisions above, a recipient may use your version
* of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the MPL as stated above or under the terms of the GNU
* Library General Public License as published by the Free Software Foundation;
* either version 2 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
* details.
*
* If you didn't download this code from the following link, you should check if
* you aren't using an obsolete version:
* https://github.com/LibrePDF/OpenPDF
*/
package com.lowagie.text.pdf.crypto;
public class ARCFOUREncryption {
private byte[] state = new byte[256];
private int x;
private int y;
/** Creates a new instance of ARCFOUREncryption */
public ARCFOUREncryption() {
}
public void prepareARCFOURKey(byte[] key) {
prepareARCFOURKey(key, 0, key.length);
}
public void prepareARCFOURKey(byte[] key, int off, int len) {
int index1 = 0;
int index2 = 0;
for (int k = 0; k < 256; ++k)
state[k] = (byte)k;
x = 0;
y = 0;
byte tmp;
for (int k = 0; k < 256; ++k) {
index2 = (key[index1 + off] + state[k] + index2) & 255;
tmp = state[k];
state[k] = state[index2];
state[index2] = tmp;
index1 = (index1 + 1) % len;
}
}
public void encryptARCFOUR(byte[] dataIn, int off, int len, byte[] dataOut, int offOut) {
int length = len + off;
byte tmp;
for (int k = off; k < length; ++k) {
x = (x + 1) & 255;
y = (state[x] + y) & 255;
tmp = state[x];
state[x] = state[y];
state[y] = tmp;
dataOut[k - off + offOut] = (byte)(dataIn[k] ^ state[(state[x] + state[y]) & 255]);
}
}
public void encryptARCFOUR(byte[] data, int off, int len) {
encryptARCFOUR(data, off, len, data, off);
}
public void encryptARCFOUR(byte[] dataIn, byte[] dataOut) {
encryptARCFOUR(dataIn, 0, dataIn.length, dataOut, 0);
}
public void encryptARCFOUR(byte[] data) {
encryptARCFOUR(data, 0, data.length, data, 0);
}
}
