org.gatherdata.commons.security.DigestFactory.java Source code

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Here is the source code for org.gatherdata.commons.security.DigestFactory.java

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/**
 * The contents of this file are subject to the AED Public Use License Agreement, Version 1.0 (the "License");
 * use in any manner is strictly prohibited except in compliance with the terms of the License.
 * The License is available at http://gatherdata.org/license.
 *
 * Copyright (c) AED.  All Rights Reserved
 */
package org.gatherdata.commons.security;

import java.io.Serializable;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Collection;

import org.apache.commons.lang.builder.EqualsBuilder;
import org.gatherdata.commons.io.MimeSerializer;

/**
 * Utility factory for calculating digests for Serializable data.
 * 
 */
public class DigestFactory {

    public static String MD2_ALGORITHM = "MD2";
    public static String MD5_ALGORITHM = "MD5";
    public static String SHA1_ALGORITHM = "SHA-1";
    public static String SHA256_ALGORITHM = "SHA-256";
    public static String SHA384_ALGORITHM = "SHA-384";
    public static String SHA512_ALGORITHM = "SHA-512";

    private static String defaultAlgorithm = SHA1_ALGORITHM;

    public static void setDefaultAlgorithm(String algorithm) throws NoSuchAlgorithmException {
        MessageDigest.getInstance(algorithm);
        defaultAlgorithm = algorithm;
    }

    public static String getDefaultAlgorithm() {
        return defaultAlgorithm;
    }

    public static boolean validate(String algorithm, byte[] expectedDigest, Serializable data)
            throws NoSuchAlgorithmException {
        boolean isValid = false;

        MessageDigest md;

        md = MessageDigest.getInstance(algorithm);

        byte[] dataAsBytes = MimeSerializer.serialize(data);
        byte[] testDigest = md.digest(dataAsBytes);
        EqualsBuilder eb = new EqualsBuilder().append(expectedDigest, testDigest);
        isValid = eb.isEquals();

        return isValid;
    }

    /**
     * Factory method to calculate a digest using a named algorithm.
     * 
     * @param data data to be sealed
     * @param usingAlgorithmNamed name of algorithm used to calculate the Seal's digest 
     * @return a digest for the data
     * @throws NoSuchAlgorithmException if the named algorithm is not supported on this platform
     */
    public static byte[] createDigestFor(Serializable data, String usingAlgorithmNamed)
            throws NoSuchAlgorithmException {

        MessageDigest md;
        byte[] dataAsBytes = MimeSerializer.serialize(data);

        md = MessageDigest.getInstance(usingAlgorithmNamed);

        byte[] digest = md.digest(dataAsBytes);

        return digest;
    }

    public static byte[] createDigestFor(Collection<? extends Serializable> data, String usingAlgorithmNamed)
            throws NoSuchAlgorithmException {

        MessageDigest md = MessageDigest.getInstance(usingAlgorithmNamed);

        for (Serializable element : data) {
            byte[] elementAsBytes = MimeSerializer.serialize(element);
            md.update(elementAsBytes);
        }

        byte[] digest = md.digest();

        return digest;
    }

    /**
     * Factory method to calculate a digest using the default algorithm.
     * 
     * @param data data to be digested
     * @return
     */
    public static byte[] createDigestFor(Serializable data) {
        byte[] digest = null;
        try {
            digest = createDigestFor(data, defaultAlgorithm);
        } catch (NoSuchAlgorithmException e) {
            System.err.println("Default algorithm \"" + defaultAlgorithm + "\" not recognized by MessageDigest");
            e.printStackTrace();
        }
        return digest;
    }

    public static byte[] createDigestFor(Collection<? extends Serializable> data) {

        byte[] digest = null;
        try {
            digest = createDigestFor(data, defaultAlgorithm);
        } catch (NoSuchAlgorithmException e) {
            System.err.println("Default algorithm \"" + defaultAlgorithm + "\" not recognized by MessageDigest");
            e.printStackTrace();
        }
        return digest;
    }

}