Java tutorial
//package com.java2s; /* * Copyright (c) 2001-2007 Sun Microsystems, Inc. All rights reserved. * * The Sun Project JXTA(TM) Software License * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * 3. The end-user documentation included with the redistribution, if any, must * include the following acknowledgment: "This product includes software * developed by Sun Microsystems, Inc. for JXTA(TM) technology." * Alternately, this acknowledgment may appear in the software itself, if * and wherever such third-party acknowledgments normally appear. * * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must * not be used to endorse or promote products derived from this software * without prior written permission. For written permission, please contact * Project JXTA at http://www.jxta.org. * * 5. Products derived from this software may not be called "JXTA", nor may * "JXTA" appear in their name, without prior written permission of Sun. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SUN * MICROSYSTEMS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * JXTA is a registered trademark of Sun Microsystems, Inc. in the United * States and other countries. * * Please see the license information page at : * <http://www.jxta.org/project/www/license.html> for instructions on use of * the license in source files. * * ==================================================================== * * This software consists of voluntary contributions made by many individuals * on behalf of Project JXTA. For more information on Project JXTA, please see * http://www.jxta.org. * * This license is based on the BSD license adopted by the Apache Foundation. */ import java.io.IOException; import java.io.InputStream; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.security.Signature; import java.security.SignatureException; import java.security.cert.Certificate; public class Main { /** * Verify a signature of a stream. * * @param cert The certificate containing the public key which will be used * to verify the signature. * @param signature The signature to verify. * @param stream The stream to verify. * @return boolean true if the signature was valid otherwise false. */ public static boolean verifySignature(String algorithm, Certificate cert, byte[] signature, InputStream stream) throws InvalidKeyException, SignatureException, IOException { Signature sign; try { sign = Signature.getInstance(algorithm); } catch (NoSuchAlgorithmException badsigner) { throw new IOException("Could not initialize signer with algorithm " + algorithm); } sign.initVerify(cert); byte[] buffer = new byte[1024]; while (true) { int read = stream.read(buffer); if (read < 0) { break; } sign.update(buffer, 0, read); } return sign.verify(signature); } }