code: /*
   * Computoser is a music-composition algorithm and a website to present the results
   * Copyright (C) 2012-2014  Bozhidar Bozhanov
   *
   * Computoser is free software: you can redistribute it and/or modify
   * it under the terms of the GNU Affero General Public License as
   * published by the Free Software Foundation, either version 3 of the
   * License, or (at your option) any later version.
   *
   * Computoser is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU Affero General Public License for more details.
   *
   * You should have received a copy of the GNU Affero General Public License
   * along with Computoser.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package com.music.util;
  
  import javax.crypto.Mac;
  import javax.crypto.spec.SecretKeySpec;
  
  import org.apache.commons.codec.binary.Hex;
  import org.apache.commons.lang3.StringUtils;
  
  public final class SecurityUtils {
  
      private static final String HMAC_SHA1_ALGORITHM = "HmacSHA1";
  
      /**
       * Calculates a HmacSHA1 value
       *
       * @param data
       * @param key
       * @return HmacSHA1
       */
      public static String hmac(String data, String key) {
          try {
              // get an hmac_sha1 key from the raw key bytes
              SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), HMAC_SHA1_ALGORITHM);
              Mac mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
              mac.init(signingKey);
  
              // compute the hmac on input data bytes
              byte[] rawHmac = mac.doFinal(data.getBytes());
  
              String result = new String(Hex.encodeHex(rawHmac));
              return result.toUpperCase();
          } catch (Exception ex) {
              throw new RuntimeException("Problem with calculating hmac", ex);
          }
      }
  
      public static void main(String[] args) {
          System.out.println(hmac(StringUtils.leftPad("5", 10, '0'), "zonUgkO8FxaPbVfESWZhfzCB"));
      }
  }
  