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 * reserved comment block

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/*

 * 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.

 *

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package com.sun.org.apache.xml.internal.security.encryption;

import java.util.Iterator;

import com.sun.org.apache.xml.internal.security.keys.KeyInfo;

import org.w3c.dom.Element;

/**

 * A Key Agreement algorithm provides for the derivation of a shared secret key

 * based on a shared secret computed from certain types of compatible public

 * keys from both the sender and the recipient. Information from the originator

 * to determine the secret is indicated by an optional OriginatorKeyInfo

 * parameter child of an <code>AgreementMethod</code> element while that

 * associated with the recipient is indicated by an optional RecipientKeyInfo. A

 * shared key is derived from this shared secret by a method determined by the

 * Key Agreement algorithm.

 * <p>

 * <b>Note:</b> XML Encryption does not provide an on-line key agreement

 * negotiation protocol. The <code>AgreementMethod</code> element can be used by

 * the originator to identify the keys and computational procedure that were

 * used to obtain a shared encryption key. The method used to obtain or select

 * the keys or algorithm used for the agreement computation is beyond the scope

 * of this specification.

 * <p>

 * The <code>AgreementMethod</code> element appears as the content of a

 * <code>ds:KeyInfo</code> since, like other <code>ds:KeyInfo</code> children,

 * it yields a key. This <code>ds:KeyInfo</code> is in turn a child of an

 * <code>EncryptedData</code> or <code>EncryptedKey</code> element. The

 * Algorithm attribute and KeySize child of the <code>EncryptionMethod</code>

 * element under this <code>EncryptedData</code> or <code>EncryptedKey</code>

 * element are implicit parameters to the key agreement computation. In cases

 * where this <code>EncryptionMethod</code> algorithm <code>URI</code> is

 * insufficient to determine the key length, a KeySize MUST have been included.

 * In addition, the sender may place a KA-Nonce element under

 * <code>AgreementMethod</code> to assure that different keying material is

 * generated even for repeated agreements using the same sender and recipient

 * public keys.

 * <p>

 * If the agreed key is being used to wrap a key, then

 * <code>AgreementMethod</code> would appear inside a <code>ds:KeyInfo</code>

 * inside an <code>EncryptedKey</code> element.

 * <p>

 * The Schema for AgreementMethod is as follows:

 * <xmp>

 * <element name="AgreementMethod" type="xenc:AgreementMethodType"/>

 * <complexType name="AgreementMethodType" mixed="true">

 *     <sequence>

 *         <element name="KA-Nonce" minOccurs="0" type="base64Binary"/>

 *         <!-- <element ref="ds:DigestMethod" minOccurs="0"/> -->

 *         <any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>

 *         <element name="OriginatorKeyInfo" minOccurs="0" type="ds:KeyInfoType"/>

 *         <element name="RecipientKeyInfo" minOccurs="0" type="ds:KeyInfoType"/>

 *     </sequence>

 *     <attribute name="Algorithm" type="anyURI" use="required"/>

 * </complexType>

 * </xmp>

 *

 * @author Axl Mattheus

 */

public interface AgreementMethod {

    /**

     * Returns an <code>byte</code> array.

     * @return

     */

    byte[] getKANonce();

    /**

     * Sets the KANonce.jj

     * @param kanonce

     */

    void setKANonce(byte[] kanonce);

    /**

     * Returns aditional information regarding the <code>AgreementMethod</code>.

     * @return

     */

    /**

     * Adds additional <code>AgreementMethod</code> information.

     *

     * @param info a <code>Element</code> that represents additional information

     * specified by

     *   <xmp>

     *     <any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>

     *   </xmp>

     */

    void addAgreementMethodInformation(Element info);

    /**

     * Removes additional <code>AgreementMethod</code> information.

     *

     * @param info a <code>Element</code> that represents additional information

     * specified by

     *   <xmp>

     *     <any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>

     *   </xmp>

     */

    void revoveAgreementMethodInformation(Element info);

    /**

     * Returns information relating to the originator's shared secret.

     *

     * @return information relating to the originator's shared secret.

     */

    KeyInfo getOriginatorKeyInfo();

    /**

     * Sets the information relating to the originator's shared secret.

     *

     * @param keyInfo information relating to the originator's shared secret.

     */

    void setOriginatorKeyInfo(KeyInfo keyInfo);

    /**

     * Retruns information relating to the recipient's shared secret.

     *

     * @return information relating to the recipient's shared secret.

     */

    KeyInfo getRecipientKeyInfo();

    /**

     * Sets the information relating to the recipient's shared secret.

     *

     * @param keyInfo information relating to the recipient's shared secret.

     */

    void setRecipientKeyInfo(KeyInfo keyInfo);

    /**

     * Returns the algorithm URI of this <code>CryptographicMethod</code>.

     *

     * @return the algorithm URI of this <code>CryptographicMethod</code>

     */

    String getAlgorithm();

}