110 lines
3.2 KiB
Java
110 lines
3.2 KiB
Java
//******************************************************************************
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//
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// File: CipherOutputStream.java
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// Package: edu.rit.crypto
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// Unit: Class edu.rit.crypto.CipherOutputStream
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//
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// This Java source file is copyright (C) 2013 by Alan Kaminsky. All rights
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// reserved. For further information, contact the author, Alan Kaminsky, at
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// ark@cs.rit.edu.
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//
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// This Java source file is part of the Parallel Java 2 Library ("PJ2"). PJ2 is
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// free software; you can redistribute it and/or modify it under the terms of
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// the GNU General Public License as published by the Free Software Foundation;
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// either version 3 of the License, or (at your option) any later version.
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//
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// PJ2 is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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//
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// A copy of the GNU General Public License is provided in the file gpl.txt. You
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// may also obtain a copy of the GNU General Public License on the World Wide
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// Web at http://www.gnu.org/licenses/gpl.html.
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//
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//******************************************************************************
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package edu.rit.crypto;
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import java.io.FilterOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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/**
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* Class CipherOutputStream provides a {@linkplain java.io.FilterOutputStream
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* FilterOutputStream} that passes all bytes written through a {@linkplain
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* StreamCipher StreamCipher}. If the bytes written to the cipher output stream
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* are plaintext, the bytes written to the underlying output stream are
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* ciphertext (encryption). If the bytes written to the cipher output stream are
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* ciphertext, the bytes written to the underlying output stream are plaintext
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* (decryption).
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*
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* @author Alan Kaminsky
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* @version 09-Aug-2013
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*/
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public class CipherOutputStream
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extends FilterOutputStream
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{
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// Hidden data members.
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private StreamCipher cipher;
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// Exported constructors.
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/**
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* Construct a new cipher output stream.
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*
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* @param out Underlying output stream.
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* @param cipher Stream cipher.
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*
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* @exception NullPointerException
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* (unchecked exception) Thrown if <TT>out</TT> is null or
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* <TT>cipher</TT> is null.
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*/
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public CipherOutputStream
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(OutputStream out,
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StreamCipher cipher)
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{
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super (validate (out));
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this.cipher = validate (cipher);
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}
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private static OutputStream validate
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(OutputStream out)
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{
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if (out == null)
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throw new NullPointerException
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("CipherOutputStream(): out is null");
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return out;
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}
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private static StreamCipher validate
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(StreamCipher cipher)
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{
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if (cipher == null)
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throw new NullPointerException
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("CipherOutputStream(): cipher is null");
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return cipher;
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}
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// Exported operations.
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/**
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* Write the given byte to this cipher output stream. Only the least
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* significant 8 bits of <TT>b</TT> are used.
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*
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* @param b Plaintext byte (if encrypting), ciphertext byte (if
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* decrypting).
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*
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* @exception IOException
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* Thrown if an I/O error occurred.
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*/
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public void write
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(int b)
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throws IOException
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{
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out.write (cipher.encrypt (b));
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}
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}
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