org.mitre.jwt.signer.impl.HmacSigner.java Source code

Introduction

Here is the source code for org.mitre.jwt.signer.impl.HmacSigner.java

Source

/*******************************************************************************
 * Copyright 2012 The MITRE Corporation
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package org.mitre.jwt.signer.impl;

import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.security.GeneralSecurityException;
import java.security.NoSuchAlgorithmException;
import java.util.List;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.mitre.jwt.signer.AbstractJwtSigner;
import org.mitre.jwt.signer.JwsAlgorithm;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;

import com.google.common.base.Splitter;
import com.google.common.collect.Lists;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

/**
 * JWT Signer using either the HMAC SHA-256, SHA-384, SHA-512 hash algorithm
 * 
 * @author AANGANES, nemonik
 * 
 */
public class HmacSigner extends AbstractJwtSigner implements InitializingBean {

    public static final String DEFAULT_PASSPHRASE = "changeit";

    public static final JwsAlgorithm DEFAULT_ALGORITHM = JwsAlgorithm.HS256;

    private static Log logger = LogFactory.getLog(HmacSigner.class);

    private Mac mac;

    private String passphrase = DEFAULT_PASSPHRASE;

    /**
     * Default constructor
     */
    public HmacSigner() {
        super(DEFAULT_ALGORITHM);
    }

    /**
     * Create HMAC singer with default algorithm and passphrase as raw bytes
     * 
     * @param passphraseAsRawBytes
     *            The passphrase as raw bytes
     */
    public HmacSigner(byte[] passphraseAsRawBytes) throws NoSuchAlgorithmException {
        this(DEFAULT_ALGORITHM.getJwaName(), new String(passphraseAsRawBytes, Charset.forName("UTF-8")));
    }

    /**
     * Create HMAC singer with default algorithm and passphrase
     * 
     * @param passwordAsRawBytes
     *            The passphrase as raw bytes
     */
    public HmacSigner(String passphrase) throws NoSuchAlgorithmException {
        this(DEFAULT_ALGORITHM.getJwaName(), passphrase);
    }

    /**
     * Create HMAC singer with given algorithm and password as raw bytes
     * 
     * @param algorithmName
     *            The Java standard name of the requested MAC algorithm
     * @param passphraseAsRawBytes
     *            The passphrase as raw bytes
     */
    public HmacSigner(String algorithmName, byte[] passphraseAsRawBytes) throws NoSuchAlgorithmException {
        this(algorithmName, new String(passphraseAsRawBytes, Charset.forName("UTF-8")));
    }

    /**
     * Create HMAC singer with given algorithm and passwords
     * 
     * @param algorithmName
     *            The Java standard name of the requested MAC algorithm
     * @param passphrase
     *            the passphrase
     */
    public HmacSigner(String algorithmName, String passphrase) {
        super(JwsAlgorithm.getByName(algorithmName));

        Assert.notNull(passphrase, "A passphrase must be supplied");

        setPassphrase(passphrase);

    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
     */
    @Override
    public void afterPropertiesSet() {
        initializeMac();
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.mitre.jwt.signer.AbstractJwtSigner#generateSignature(java.lang.String
     * )
     */
    @Override
    public String generateSignature(String signatureBase) throws NoSuchAlgorithmException {

        initializeMac();

        if (passphrase == null) {
            throw new IllegalArgumentException("Passphrase cannot be null");
        }

        try {
            mac.init(new SecretKeySpec(getPassphrase().getBytes(), mac.getAlgorithm()));

            mac.update(signatureBase.getBytes("UTF-8"));
        } catch (GeneralSecurityException e) {
            logger.error(e);
        } catch (UnsupportedEncodingException e) {
            logger.error(e);
        }

        byte[] sigBytes = mac.doFinal();

        String sig = new String(Base64.encodeBase64URLSafe(sigBytes));

        // strip off any padding
        sig = sig.replace("=", "");

        return sig;
    }

    public String getPassphrase() {
        return passphrase;
    }

    public void setPassphrase(byte[] rawbytes) {
        this.setPassphrase(new String(rawbytes, Charset.forName("UTF-8")));
    }

    public void setPassphrase(String passphrase) {
        this.passphrase = passphrase;
    }

    private void initializeMac() {
        if (mac == null) {
            try {
                mac = Mac.getInstance(getAlgorithm().getStandardName());
            } catch (NoSuchAlgorithmException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return "HmacSigner [mac=" + mac + ", passphrase=" + passphrase + "]";
    }
}