TwoFactorSecretGenerator.java

/*******************************************************************************
 * Copyright (c) 2013, 2014 Lectorius, Inc.
 * Authors:
 * Vijay Pandurangan (vijayp@mitro.co)
 * Evan Jones (ej@mitro.co)
 * Adam Hilss (ahilss@mitro.co)
 *
 *
 *     This program is free software: you can redistribute it and/or modify
 *     it under the terms of the 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
 *     GNU General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *     
 *     You can contact the authors at inbound@mitro.co.
 *******************************************************************************/
package co.mitro.twofactor;

import java.security.SecureRandom;
import java.util.Arrays;

import org.apache.commons.codec.binary.Base32;

import com.google.common.base.Charsets;

public class TwoFactorSecretGenerator {
  private final static int SECRET_SIZE = 20;    // 160 bits to match SHA-1 size.
  private final static SecureRandom secureRandom = new SecureRandom();

  public static String generateSecretKey() {
    byte[] buffer = new byte[SECRET_SIZE];
    secureRandom.nextBytes(buffer);
    Base32 codec = new Base32();
    byte[] secretKey = Arrays.copyOf(buffer, SECRET_SIZE);
    byte[] bEncodedKey = codec.encode(secretKey);
    String encodedKey = new String(bEncodedKey, Charsets.UTF_8);
    return encodedKey;
  }
}