Android Open Source - APO-Theta-Upsilon-App Hmac

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License

The source code is released under:

GNU Lesser General Public License

Java Source Code

/*
 * Copyright 2011 Devin Schwab, Umang Banugaria
 *//from ww  w.ja v  a 2 s .c  om
 * This file is part of the APO Theta Upsilon App for Case Western Reserve University's Alpha Phi Omega Theta Upsilon Chapter.
 *
 * The APO Theta Upsilon program is free software: you can redistribute it and/or modify
 * it under the terms of the Lesser GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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
 * Lesser GNU General Public License for more details.
 *
 * You should have received a copy of the Lesser GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package edu.cwru.apo;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

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

public class Hmac {
  
  protected byte[] secretKey = null;
  protected int defaultKeyLength = 128;
  protected String mode = "HmacSHA1";
  
  public Hmac()
  {
    SecureRandom random = new SecureRandom();
    secretKey = new byte[defaultKeyLength];
    random.nextBytes(secretKey);
  }
  
  public Hmac(String mode, int keyLength)
  {
    SecureRandom random = new SecureRandom();
    secretKey = new byte[keyLength];
    random.nextBytes(secretKey);
    this.mode = mode;
  }
  
  public Hmac(String mode, Hex secretKey)
  {
    this.secretKey = secretKey.toBytes();
    this.mode = mode;
  }
  
  public Hex getSecretKey()
  {
    return new Hex(secretKey);
  }
  
  public String getMode()
  {
    return mode;
  }
  
  // NOTE: this does not check if provided secret key is valid
  public void setKey(Hex secretKey)
  {
    this.secretKey = secretKey.toBytes();
  }
  
  // NOTE: this does not check if provided mode is valid
  public void setMode(String mode)
  {
    this.mode = mode;
  }
  
  public Hex generate(String data) throws InvalidKeyException,NoSuchAlgorithmException
  {
    if(secretKey == null)
      return null;
    SecretKeySpec sk = new SecretKeySpec(secretKey, mode);
    Mac mac;
    mac = Mac.getInstance(mode);
      mac.init(sk);

      return new Hex(mac.doFinal(data.getBytes()));
  }

}

Java Source Code List

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