OstermillerUtils Java Utilities - MD5OutputStream.java Source Code

MD5OutputStream.java Source Code

MD5 Documentation and Examples
MD5OutputStream Javadoc
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/*
 * Copyright (C) 1996 Santeri Paavolainen, Helsinki Finland
 *
 * Copyright (C) 2002-2010 Stephen Ostermiller
 * http://ostermiller.org/contact.pl?regarding=Java+Utilities
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * See LICENSE.txt for details.
 *
 * The original work by Santeri Paavolainen can be found a
 * http://santtu.iki.fi/md5/
 */
package com.Ostermiller.util;
 
import java.io.*;
 
/**
 * Implements MD5 functionality on a stream.
 * More information about this class is available from <a target="_top" href=
 * "http://ostermiller.org/utils/MD5.html">ostermiller.org</a>.
 * <p>
 * This class produces a 128-bit "fingerprint" or "message digest" for
 * all data written to this stream.
 * It is conjectured that it is computationally infeasible to produce
 * two messages having the same message digest, or to produce any
 * message having a given pre-specified target message digest. The MD5
 * algorithm is intended for digital signature applications, where a
 * large file must be "compressed" in a secure manner before being
 * encrypted with a private (secret) key under a public-key cryptosystem
 * such as RSA.
 * <p>
 * For more information see RFC1321.
 *
 * @see MD5
 * @see MD5InputStream
 *
 * @author Santeri Paavolainen http://santtu.iki.fi/md5/
 * @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
 * @since ostermillerutils 1.00.00
 */
public class MD5OutputStream extends FilterOutputStream {
 
    /**
     * MD5 context
     */
    private MD5 md5;
 
    /**
     * Creates MD5OutputStream
     * @param out   The output stream
     *
     * @since ostermillerutils 1.00.00
     */
    public MD5OutputStream(OutputStream out) {
        super(out);
        md5 = new MD5();
    }
 
    /**
     * Writes the specified byte to this output stream.
     *
     * @param b the byte.
     * @throws IOException if an I/O error occurs.
     *
     * @since ostermillerutils 1.00.00
     */
    @Override public void write(int b) throws IOException {
        out.write(b);
        md5.update((byte)(b & 0xff));
    }
 
    /**
     * Writes length bytes from the specified byte array starting a
     * offset off to this output stream.
     *
     * @param b the data.
     * @param off the start offset in the data.
     * @param len the number of bytes to write.
     * @throws IOException if an I/O error occurs.
     *
     * @since ostermillerutils 1.00.00
     */
    @Override public void write(byte b[], int off, int len) throws IOException {
        out.write(b, off, len);
        md5.update(b, off, len);
    }
 
    /**
     * Returns array of bytes representing hash of the stream so far.
     *
     * @return Array of 16 bytes, the hash of all written bytes.
     *
     * @since ostermillerutils 1.00.00
     */
    public byte[] getHash(){
        return md5.getHash();
    }
 
    /**
     * Get a 32-character hex representation representing hash of the stream so far.
     *
     * @return A string containing  the hash of all written bytes.
     *
     * @since ostermillerutils 1.00.00
     */
    public String getHashString(){
        return md5.getHashString();
    }
}
OstermillerUtils

Documentation

MD5OutputStream.java Source Code
