111 lines
4.4 KiB
C#
111 lines
4.4 KiB
C#
using System;
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using iTextSharp.text.pdf.crypto;
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/*
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* $Id: StandardDecryption.cs,v 1.3 2007/04/29 13:57:12 psoares33 Exp $
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*
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* Copyright 2006 Paulo Soares
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*
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* The contents of this file are subject to the Mozilla Public License Version 1.1
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* (the "License"); you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the License.
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*
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* The Original Code is 'iText, a free JAVA-PDF library'.
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*
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* The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
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* the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
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* All Rights Reserved.
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* Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
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* are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
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*
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* Contributor(s): all the names of the contributors are added in the source code
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* where applicable.
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*
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* Alternatively, the contents of this file may be used under the terms of the
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* LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
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* provisions of LGPL are applicable instead of those above. If you wish to
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* allow use of your version of this file only under the terms of the LGPL
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* License and not to allow others to use your version of this file under
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* the MPL, indicate your decision by deleting the provisions above and
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* replace them with the notice and other provisions required by the LGPL.
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* If you do not delete the provisions above, a recipient may use your version
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* of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
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*
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* This library is free software; you can redistribute it and/or modify it
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* under the terms of the MPL as stated above or under the terms of the GNU
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* Library General Public License as published by the Free Software Foundation;
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* either version 2 of the License, or any later version.
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*
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* This library is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
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* details.
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*
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* If you didn't download this code from the following link, you should check if
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* you aren't using an obsolete version:
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* http://www.lowagie.com/iText/
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*/
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namespace iTextSharp.text.pdf.crypto {
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public class StandardDecryption {
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protected ARCFOUREncryption arcfour;
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protected AESCipher cipher;
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private byte[] key;
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private const int AES_128 = 4;
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private bool aes;
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private bool initiated;
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private byte[] iv = new byte[16];
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private int ivptr;
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/** Creates a new instance of StandardDecryption */
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public StandardDecryption(byte[] key, int off, int len, int revision) {
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aes = revision == AES_128;
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if (aes) {
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this.key = new byte[len];
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System.Array.Copy(key, off, this.key, 0, len);
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}
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else {
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arcfour = new ARCFOUREncryption();
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arcfour.PrepareARCFOURKey(key, off, len);
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}
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}
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public byte[] Update(byte[] b, int off, int len) {
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if (aes) {
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if (initiated)
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return cipher.Update(b, off, len);
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else {
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int left = Math.Min(iv.Length - ivptr, len);
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System.Array.Copy(b, off, iv, ivptr, left);
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off += left;
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len -= left;
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ivptr += left;
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if (ivptr == iv.Length) {
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cipher = new AESCipher(false, key, iv);
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initiated = true;
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if (len > 0)
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return cipher.Update(b, off, len);
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}
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return null;
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}
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}
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else {
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byte[] b2 = new byte[len];
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arcfour.EncryptARCFOUR(b, off, len, b2, 0);
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return b2;
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}
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}
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public byte[] Finish() {
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if (aes) {
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return cipher.DoFinal();
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}
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else
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return null;
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}
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}
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} |