HashStrategy.java

/*
 * Copyright 2018 Red Hat, Inc.
 *
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  and Apache License v2.0 which accompanies this distribution.
 *
 *  The Eclipse Public License is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 *
 *  The Apache License v2.0 is available at
 *  http://www.opensource.org/licenses/apache2.0.php
 *
 *  You may elect to redistribute this code under either of these licenses.
 */
package io.vertx.ext.auth.jdbc;

/**
 * A more generic HashStrategy to supersede {@link JDBCHashStrategy}
 *
 * @author <a href="https://github.com/sonOfRa">Simon Levermann</a>
 */
public interface HashStrategy {

  /**
   * Hash the given password.
   *
   * @param password the password to hash
   * @return a string representation of the password, containing all necessary information to verify it again
   */
  String hash(String password);

  /**
   * Verify a password against a stored hash String, as returned by {@link #hash(String)}
   *
   * @param plainPassword the password to verify
   * @param storedHash    the hash to verify against
   * @return true if the password matches, false otherwise
   */
  boolean verify(String plainPassword, String storedHash);

  /**
   * Check whether a given password needs to be rehashed.
   * <p>
   * Modern password hashing algorithms come with a plethora of configuration options. These should be passed
   * to the constructor of an implementation of this interface. The parameters should be stored alongside the hash,
   * (the hashing functions generally take care of this) and these can then be compared to the settings stored in the
   * HashStrategy.
   * <p>
   * This method can be used when a user logs in, as in this case the plaintext password is available. If it returns
   * true, the program can send it through {@link #hash(String)} again to reset it to the new version (after verifying
   * of course!)
   *
   * @param storedHash the hash to check
   * @return true if the parameters in the stored hash don't match the parameters given to the strategy
   */
  boolean needsRehash(String storedHash);
}