defaultpasswordencoder.java

来自「CAS在Tomcat中实现单点登录项目,单点登录（Single Sign On 」· Java 代码 · 共 69 行

/*
 * Copyright 2007 The JA-SIG Collaborative. All rights reserved. See license
 * distributed with this file and available online at
 * http://www.uportal.org/license.html
 */
package org.jasig.cas.authentication.handler;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.jasig.cas.util.annotation.NotNull;

/**
 * Implementation of PasswordEncoder using message digest. Can accept any
 * message digest that the JDK can accept, including MD5 and SHA1. Returns the
 * equivalent Hash you would get from a Perl digest.
 * 
 * @author Scott Battaglia
 * @author Stephen More
 * @version $Revision: 42053 $ $Date: 2007-06-10 09:17:55 -0400 (Sun, 10 Jun 2007) $
 * @since 3.1
 */
public final class DefaultPasswordEncoder implements PasswordEncoder {

    private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5',
        '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

    @NotNull
    private final String encodingAlgorithm;

    public DefaultPasswordEncoder(final String encodingAlgorithm) {
        this.encodingAlgorithm = encodingAlgorithm;
    }

    public String encode(final String password) {
        if (password == null) {
            return null;
        }

        try {
            MessageDigest messageDigest = MessageDigest
                .getInstance(this.encodingAlgorithm);
            messageDigest.update(password.getBytes());

            final byte[] digest = messageDigest.digest();

            return getFormattedText(digest);
        } catch (NoSuchAlgorithmException e) {
            throw new SecurityException(e);
        }
    }

    /**
     * Takes the raw bytes from the digest and formats them correct.
     * 
     * @param bytes the raw bytes from the digest.
     * @return the formatted bytes.
     */
    private String getFormattedText(byte[] bytes) {
        final StringBuilder buf = new StringBuilder(bytes.length * 2);

        for (int j = 0; j < bytes.length; j++) {
            buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
            buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
        }
        return buf.toString();
    }
}