com.itextpdf.text.pdf.crypto.IVGenerator Maven / Gradle / Ivy
/*
* $Id: 641f7ffdac33d71499734b85e2c2bfc5544389e1 $
*
* This file is part of the iText (R) project.
* Copyright (c) 1998-2016 iText Group NV
* Authors: Bruno Lowagie, Paulo Soares, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
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* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General Public License.
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* a covered work must retain the producer line in every PDF that is created
* or manipulated using iText.
*
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package com.itextpdf.text.pdf.crypto;
/**
* An initialization vector generator for a CBC block encryption. It's a random generator based on ARCFOUR.
* @author Paulo Soares
*/
public final class IVGenerator {
private static ARCFOUREncryption arcfour;
static {
arcfour = new ARCFOUREncryption();
long time = System.currentTimeMillis();
long mem = Runtime.getRuntime().freeMemory();
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
*/
public static byte[] getIV(int len) {
byte[] b = new byte[len];
synchronized (arcfour) {
arcfour.encryptARCFOUR(b);
}
return b;
}
}