com.rsmart.rfabric.jasperreports.auth.Signature.java Source code

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Here is the source code for com.rsmart.rfabric.jasperreports.auth.Signature.java

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/*
 * 
 * Derived from source found at: <a href=
 * "http://github.com/sakaiproject/nakamura/blob/master/libraries/utils/src/main/java/org/sakaiproject/nakamura/util/Signature.java"
 * >nakamura/libraries/utils/src/main/java/org/sakaiproject/nakamura/util/
 * Signature.java@70078352b144921ee03a4f2e1d17a3a9b9a2b231</a>
 * 
 * Licensed to the Sakai Foundation (SF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The SF licenses this file
 * to you 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 com.rsmart.rfabric.jasperreports.auth;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

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

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Utility to calculate signatures for information.
 */
@SuppressWarnings("PMD.LongVariable")
public class Signature {
    private static final Log LOG = LogFactory.getLog(Signature.class);
    protected transient String hmacSha1Algorithm = "HmacSHA1";
    private transient Mac mac;

    /**
     * @throws IllegalStateException
     *             If there are any run time problems getting an instance.
     */
    public Signature() {
        instatiateMac();
    }

    private void instatiateMac() {
        try {
            // Get an hmac_sha1 Mac instance
            mac = Mac.getInstance(hmacSha1Algorithm);
        } catch (NoSuchAlgorithmException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Intended to be used for unit testing only.
     * 
     * @param algorithm
     */
    protected Signature(final String algorithm) {
        this.hmacSha1Algorithm = algorithm;
        instatiateMac();
    }

    /**
     * Calculate an RFC2104 compliant HMAC (Hash-based Message Authentication
     * Code)
     * 
     * @param data
     *            The data to be signed. This data is pushed through a hex
     *            converter in this method, so there is no need to do this
     *            before generating the HMAC.
     * @param key
     *            The signing key.
     * @return The Base64-encoded RFC 2104-compliant HMAC signature. By default
     *            it is not URL safe.
     * @throws InvalidKeyException
     *            This is the exception for invalid Keys (invalid encoding,
     *            wrong length, uninitialized, etc).
     * @see #calculateRFC2104HMACWithEncoding(String, String, boolean)
     */
    public String calculateRFC2104HMAC(final String data, final String key) throws InvalidKeyException {
        return calculateRFC2104HMACWithEncoding(data, key, false);
    }

    /**
     * Calculate an RFC2104 compliant HMAC (Hash-based Message Authentication
     * Code)
     * 
     * @param data
     *            The data to be signed. This data is pushed through a hex
     *            converter in this method, so there is no need to do this
     *            before generating the HMAC.
     * @param key
     *            The signing key.
     * @param urlSafe
     *            true if the token needs to be URL safe.
     * @return The Base64-encoded RFC 2104-compliant HMAC signature.
     * @throws InvalidKeyException
     *             This is the exception for invalid Keys (invalid encoding,
     *             wrong length, uninitialized, etc).
     */
    @SuppressWarnings("PMD.DataflowAnomalyAnalysis")
    public String calculateRFC2104HMACWithEncoding(final String data, final String key, final boolean urlSafe)
            throws InvalidKeyException {
        if (data == null) {
            throw new IllegalArgumentException("String data == null");
        }
        if (key == null) {
            throw new IllegalArgumentException("String key == null");
        }
        String result = null;
        try {
            // Get an hmac_sha1 key from the raw key bytes
            final byte[] keyBytes = key.getBytes("UTF-8");
            final SecretKeySpec signingKey = new SecretKeySpec(keyBytes, hmacSha1Algorithm);

            // initialize with the signing key
            mac.init(signingKey);

            // Compute the hmac on input data bytes
            final byte[] rawHmac = mac.doFinal(data.getBytes());

            // Convert raw bytes to Hex
            byte[] hexBytes = new Hex().encode(rawHmac);

            // Convert raw bytes to encoding
            final byte[] base64Bytes = Base64.encodeBase64(hexBytes, false, urlSafe);
            result = new String(base64Bytes, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            LOG.error(e.getMessage(), e);
        }
        return result;
    }

}