hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/util/RandomSignerSecretProvider.java

/**
 * 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. See accompanying LICENSE file.
 */
package org.apache.hadoop.security.authentication.util;

import com.google.common.annotations.VisibleForTesting;

import java.security.SecureRandom;
import java.util.Random;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

/**
 * A SignerSecretProvider that uses a random number as its secret.  It rolls
 * the secret at a regular interval.
 */
@InterfaceStability.Unstable
@InterfaceAudience.Private
public class RandomSignerSecretProvider extends RolloverSignerSecretProvider {

  private final Random rand;

  public RandomSignerSecretProvider() {
    super();
    rand = new SecureRandom();
  }

  /**
   * This constructor lets you set the seed of the Random Number Generator and
   * is meant for testing.
   * @param seed the seed for the random number generator
   */
  @VisibleForTesting
  public RandomSignerSecretProvider(long seed) {
    super();
    rand = new Random(seed);
  }

  @Override
  protected byte[] generateNewSecret() {
    byte[] secret = new byte[32]; // 32 bytes = 256 bits
    rand.nextBytes(secret);
    return secret;
  }
}