com.aowagie.text.pdf.crypto.IVGenerator Maven / Gradle / Ivy
/*
* $Id: IVGenerator.java 3242 2008-04-13 23:00:20Z 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:
* http://www.lowagie.com/iText/
*/
package com.aowagie.text.pdf.crypto;
/**
* An initialization vector generator for a CBC block encryption. It's a random generator based on ARCFOUR.
* @author Paulo Soares ([email protected])
*/
public final class IVGenerator {
private static ARCFOUREncryption arcfour;
static {
arcfour = new ARCFOUREncryption();
final long time = System.currentTimeMillis();
final long mem = Runtime.getRuntime().freeMemory();
final String s = time + "+" + mem;
arcfour.prepareARCFOURKey(s.getBytes());
}
/** Creates a new instance of IVGenerator */
private IVGenerator() {
}
/**
* Gets a 16 byte random initialization vector.
* @return a 16 byte random initialization vector
*/
public static byte[] getIV() {
return getIV(16);
}
/**
* Gets a random initialization vector.
* @param len the length of the initialization vector
* @return a random initialization vector
*/
private static byte[] getIV(final int len) {
final byte[] b = new byte[len];
synchronized (arcfour) {
arcfour.encryptARCFOUR(b);
}
return b;
}
}