/*
 * Copyright  2003-2004 The Apache Software Foundation.
 *
 *  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.
 *
 */
package org.apache.xml.security.encryption;



/**
 * The <code>EncryptedKey</code> element is used to transport encryption keys
 * from the originator to a known recipient(s). It may be used as a stand-alone
 * XML document, be placed within an application document, or appear inside an
 * <code>EncryptedData</code> element as a child of a <code>ds:KeyInfo</code>
 * element. The key value is always encrypted to the recipient(s). When
 * <code>EncryptedKey</code> is decrypted the resulting octets are made
 * available to the <code>EncryptionMethod</code> algorithm without any
 * additional processing.
 * <p>
 * Its schema definition is as follows:
 * <xmp>
 * <element name='EncryptedKey' type='xenc:EncryptedKeyType'/>
 * <complexType name='EncryptedKeyType'>
 *     <complexContent>
 *         <extension base='xenc:EncryptedType'>
 *             <sequence>
 *                 <element ref='xenc:ReferenceList' minOccurs='0'/>
 *                 <element name='CarriedKeyName' type='string' minOccurs='0'/>
 *             </sequence>
 *             <attribute name='Recipient' type='string' use='optional'/>
 *         </extension>
 *     </complexContent>
 * </complexType>
 * </xmp>
 *
 * @author Axl Mattheus
 */
public interface EncryptedKey extends EncryptedType {
    /**
     * Returns a hint as to which recipient this encrypted key value is intended
     * for.
     *
     * @return the recipient of the <code>EncryptedKey</code>.
     */
    String getRecipient();

    /**
     * Sets the recipient for this <code>EncryptedKey</code>.
     *
     * @param recipient the recipient for this <code>EncryptedKey</code>.
     */
    void setRecipient(String recipient);

    /**
     * Returns pointers to data and keys encrypted using this key. The reference
     * list may contain multiple references to <code>EncryptedKey</code> and
     * <code>EncryptedData</code> elements. This is done using
     * <code>KeyReference</code> and <code>DataReference</code> elements
     * respectively.
     *
     * @return an <code>Iterator</code> over all the <code>ReferenceList</code>s
     *   contained in this <code>EncryptedKey</code>.
     */
    ReferenceList getReferenceList();

    /**
     * Sets the <code>ReferenceList</code> to the <code>EncryptedKey</code>.
     *
     * @param list a list of pointers to data elements encrypted using this key.
     */
    void setReferenceList(ReferenceList list);

    /**
     * Returns a user readable name with the key value. This may then be used to
     * reference the key using the <code>ds:KeyName</code> element within
     * <code>ds:KeyInfo</code>. The same <code>CarriedKeyName</code> label,
     * unlike an ID type, may occur multiple times within a single document. The
     * value of the key is to be the same in all <code>EncryptedKey</code>
     * elements identified with the same <code>CarriedKeyName</code> label
     * within a single XML document.
     * <br>
     * <b>Note</b> that because whitespace is significant in the value of
     * the <code>ds:KeyName</code> element, whitespace is also significant in
     * the value of the <code>CarriedKeyName</code> element.
     *
     * @return over all the carried names contained in
     *   this <code>EncryptedKey</code>.
     */
    String getCarriedName();

    /**
     * Sets the carried name.
     *
     * @param name the carried name.
     */
    void setCarriedName(String name);
}

