/*
 * $Id$
 *
 * Copyright 2006 Paulo Soares
 *
 *
 * 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.
 *
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) 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.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301, USA.
 *
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) 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.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301, USA.
 *
 *
 * 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 pdftk.com.lowagie.text.pdf.crypto;

import pdftk.org.bouncycastle.crypto.BlockCipher;
import pdftk.org.bouncycastle.crypto.engines.AESFastEngine;
import pdftk.org.bouncycastle.crypto.modes.CBCBlockCipher;
import pdftk.org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import pdftk.org.bouncycastle.crypto.params.KeyParameter;
import pdftk.org.bouncycastle.crypto.params.ParametersWithIV;

/**
 * Creates an AES Cipher with CBC and padding PKCS5/7.
 * @author Paulo Soares (psoares@consiste.pt)
 */
public class AESCipher {
    private PaddedBufferedBlockCipher bp;
    
    /** Creates a new instance of AESCipher */
    public AESCipher(boolean forEncryption, byte[] key, byte[] iv) {
        BlockCipher aes = new AESFastEngine();
        BlockCipher cbc = new CBCBlockCipher(aes);
        bp = new PaddedBufferedBlockCipher(cbc);
        KeyParameter kp = new KeyParameter(key);
        ParametersWithIV piv = new ParametersWithIV(kp, iv);
        bp.init(forEncryption, piv);
    }
    
    public byte[] update(byte[] inp, int inpOff, int inpLen) {
        int neededLen = bp.getUpdateOutputSize(inpLen);
        byte[] outp = null;
        if (neededLen > 0)
            outp = new byte[neededLen];
        else
            neededLen = 0;
        bp.processBytes(inp, inpOff, inpLen, outp, 0);
        return outp;
    }
    
    public byte[] doFinal() {
        int neededLen = bp.getOutputSize(0);
        byte[] outp = new byte[neededLen];
        int n = 0;
        try {
            n = bp.doFinal(outp, 0);
        } catch (Exception ex) {
            return outp;
        }
        if (n != outp.length) {
            byte[] outp2 = new byte[n];
            System.arraycopy(outp, 0, outp2, 0, n);
            return outp2;
        }
        else
            return outp;
    }
    
}
