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
020package org.apache.shiro.crypto.cipher;
021
022/**
023 * ByteSourceBroker holds an encrypted value to decrypt it on demand.
024 * <br/>
025 * {@link #useBytes(ByteSourceUser)} method is designed for dictating
026 * developers to use the byte source in a special way, to prevent its prevalence
027 * and difficulty of managing & zeroing that critical information at end of use.
028 * <br/>
029 * For exceptional cases we allow developers to use the other method,
030 * {@link #getClonedBytes()}, but it's not advised.
031 */
032public interface ByteSourceBroker {
033    /**
034     * This method accepts an implementation of ByteSourceUser functional interface.
035     * <br/>
036     * To limit the decrypted value's existence, developers should maintain the
037     * implementation part as short as possible.
038     *
039     * @param user Implements a use-case for the decrypted value.
040     */
041    void useBytes(ByteSourceUser user);
042
043    /**
044     * As the name implies, this returns a cloned byte array
045     * and caller has a responsibility to wipe it out at end of use.
046     */
047    byte[] getClonedBytes();
048}