001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    package org.apache.shiro.authc;
020    
021    import org.apache.shiro.util.ByteSource;
022    
023    /**
024     * Interface representing account information that may use a salt when hashing credentials.  This interface
025     * exists primarily to support environments that hash user credentials (e.g. passwords).
026     * <p/>
027     * Salts should typically be generated from a secure pseudo-random number generator so they are effectively
028     * impossible to guess.  The salt value should be safely stored along side the account information to ensure
029     * it is maintained along with the account's credentials.
030     * <p/>
031     * This interface exists as a way for Shiro to acquire that salt so it can correctly perform
032     * {@link org.apache.shiro.authc.credential.CredentialsMatcher credentials matching} during login attempts.
033     * See the {@link org.apache.shiro.authc.credential.HashedCredentialsMatcher HashedCredentialsMatcher} JavaDoc for
034     * more information on hashing credentials with salts.
035     *
036     * @see org.apache.shiro.authc.credential.HashedCredentialsMatcher
037     *
038     * @since 1.1
039     */
040    public interface SaltedAuthenticationInfo extends AuthenticationInfo {
041    
042        /**
043         * Returns the salt used to salt the account's credentials or {@code null} if no salt was used.
044         *
045         * @return the salt used to salt the account's credentials or {@code null} if no salt was used.
046         */
047        ByteSource getCredentialsSalt();
048    }