com.lehman.ic9.common.base64.java Source code

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Here is the source code for com.lehman.ic9.common.base64.java

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/*
 * Copyright 2016 Austin Lehman
 * 
 * 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 com.lehman.ic9.common;

import org.apache.commons.codec.binary.Base64;

import com.lehman.ic9.ic9exception;

import java.security.SignatureException;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

/**
 * Support for base64 operations.
 * @author Austin Lehman
 */
public class base64 {
    private static final String HMAC_SHA1_ALGORITHM = "HmacSHA1";

    /**
     * Base64 encodes the provided byte array and returns 
     * the encoded string. This method also hex encodes 
     * the resulting base64 data.
     * @param data is a byte[] with the data to encode.
     * @return A String with the Base64 encoded data.
     */
    public static String encode(byte[] data) {
        return new String(hex.encode(Base64.encodeBase64(data)));
    }

    /**
     * Base64 encodes the provided byte array and returns 
     * the encoded string.
     * @param data is the raw byte array data to encode.
     * @return A String with the Base64 encoded data.
     */
    public static String encodeRaw(byte[] data) {
        return new String(Base64.encodeBase64(data));
    }

    /**
     * Decodes the provided Base64 encoded string and returns 
     * a byte[] with the data. This method also hex decodes 
     * the provided data.
     * @param str is a String to decode.
     * @return A byte[] with the decoded data.
     * @throws ic9exception Exception
     */
    public static byte[] decode(String str) throws ic9exception {
        return Base64.decodeBase64(hex.decode(str));
    }

    /**
     * Decodes the provided Base64 encoded string and returns 
     * a byte[] with the data.
     * @param str is a String to decode.
     * @return A byte[] with the decoded data.
     */
    public static byte[] decodeRaw(String str) {
        return Base64.decodeBase64(str.getBytes());
    }

    /**
     * Computes RFC 2104-compliant HMAC signature.
     * @param data Is a String with the data to encode.
     * @param key Is a String with the key.
     * @return A string with the encoded signature.
     * @throws SignatureException Exception
     */
    public static String encodeHmac(String data, String key) throws java.security.SignatureException {
        String result;
        try {
            // get an hmac_sha1 key from the raw key bytes
            SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), HMAC_SHA1_ALGORITHM);

            // get an hmac_sha1 Mac instance and initialize with the signing key
            Mac mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
            mac.init(signingKey);

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

            // base64-encode the hmac
            result = new String(Base64.encodeBase64(rawHmac));
        } catch (Exception e) {
            throw new SignatureException("Failed to generate HMAC : " + e.getMessage());
        }
        return result;
    }
}