/*

 * Copyright 2000-2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

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 */

package org.ietf.jgss;

/**

 * This interface encapsulates the GSS-API credentials for an entity.  A

 * credential contains all the necessary cryptographic information to

 * enable the creation of a context on behalf of the entity that it

 * represents.  It may contain multiple, distinct, mechanism specific

 * credential elements, each containing information for a specific

 * security mechanism, but all referring to the same entity. A credential

 * may be used to perform context initiation, acceptance, or both.<p>

 *

 * Credentials are instantiated using one of the

 * <code>createCredential</code> methods in the {@link GSSManager

 * GSSManager} class. GSS-API credential creation is not

 * intended to provide a "login to the network" function, as such a

 * function would involve the creation of new credentials rather than

 * merely acquiring a handle to existing credentials. The

 * <a href=package-summary.html#useSubjectCredsOnly>section on credential

 * acquisition</a> in the package level description describes

 * how existing credentials are acquired in the Java platform. GSS-API

 * implementations must impose a local access-control policy on callers to

 * prevent unauthorized callers from acquiring credentials to which they

 * are not entitled. <p>

 *

 * Applications will create a credential object passing the desired

 * parameters.  The application can then use the query methods to obtain

 * specific information about the instantiated credential object.

 * When the credential is no longer needed, the application should call

 * the {@link #dispose() dispose} method to release any resources held by

 * the credential object and to destroy any cryptographically sensitive

 * information.<p>

 *

 * This example code demonstrates the creation of a GSSCredential

 * implementation for a specific entity, querying of its fields, and its

 * release when it is no longer needed:<p>

 * <pre>

 *    GSSManager manager = GSSManager.getInstance();

 *

 *    // start by creating a name object for the entity

 *    GSSName name = manager.createName("myusername", GSSName.NT_USER_NAME);

 *

 *    // now acquire credentials for the entity

 *    GSSCredential cred = manager.createCredential(name,

 *                    GSSCredential.ACCEPT_ONLY);

 *

 *    // display credential information - name, remaining lifetime,

 *    // and the mechanisms it has been acquired over

 *    System.out.println(cred.getName().toString());

 *    System.out.println(cred.getRemainingLifetime());

 *

 *    Oid [] mechs = cred.getMechs();

 *    if (mechs != null) {

 *            for (int i = 0; i < mechs.length; i++)

 *                    System.out.println(mechs[i].toString());

 *    }

 *

 *    // release system resources held by the credential

 *    cred.dispose();

 * </pre>

 *

 * @see GSSManager#createCredential(int)

 * @see GSSManager#createCredential(GSSName, int, Oid, int)

 * @see GSSManager#createCredential(GSSName, int, Oid[], int)

 * @see #dispose()

 *

 * @author Mayank Upadhyay

 * @since 1.4

 */

public interface GSSCredential extends Cloneable{

    /**

     * Credential usage flag requesting that it be usable

     * for both context initiation and acceptance.

     *

     */

    public static final int INITIATE_AND_ACCEPT = 0;

    /**

     * Credential usage flag requesting that it be usable

     * for context initiation only.

     *

     */

    public static final int INITIATE_ONLY = 1;

    /**

     * Credential usage flag requesting that it be usable

     * for context acceptance only.

     *

     */

    public static final int ACCEPT_ONLY = 2;

    /**

     * A lifetime constant representing the default credential lifetime. This

     * value it set to 0.

     */

    public static final int DEFAULT_LIFETIME = 0;

    /**

     * A lifetime constant representing indefinite credential lifetime.

     * This value must is set to the maximum integer value in Java -

     * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.

     */

    public static final int INDEFINITE_LIFETIME = Integer.MAX_VALUE;

    /**

     * Releases any sensitive information that the GSSCredential object may

     * be containing.  Applications should call this method as soon as the

     * credential is no longer needed to minimize the time any sensitive

     * information is maintained.

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public void dispose() throws GSSException;

    /**

     *  Retrieves the name of the entity that the credential asserts.

     *

     * @return a GSSName representing the entity

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public GSSName getName() throws GSSException;

    /**

     * Retrieves a Mechanism Name of the entity that the credential

     * asserts. This is equivalent to calling {@link

     * GSSName#canonicalize(Oid) canonicalize} on the value returned by

     * the other form of {@link #getName() getName}.

     *

     * @param mech the Oid of the mechanism for which the Mechanism Name

     * should be returned.

     * @return a GSSName representing the entity canonicalized for the

     * desired mechanism

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#BAD_MECH GSSException.BAD_MECH},

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public GSSName getName(Oid mech) throws GSSException;

    /**

     * Returns the remaining lifetime in seconds for a credential.  The

     * remaining lifetime is the minimum lifetime amongst all of the underlying

     * mechanism specific credential elements.

     *

     * @return the minimum remaining lifetime in seconds for this

     * credential. A return value of {@link #INDEFINITE_LIFETIME

     * INDEFINITE_LIFETIME} indicates that the credential does

     * not expire. A return value of 0 indicates that the credential is

     * already expired.

     *

     * @see #getRemainingInitLifetime(Oid)

     * @see #getRemainingAcceptLifetime(Oid)

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public int getRemainingLifetime() throws GSSException;

    /**

     * Returns the lifetime in seconds for the credential to remain capable

     * of initiating security contexts using the specified mechanism. This

     * method queries the initiator credential element that belongs to the

     * specified mechanism.

     *

     * @return the number of seconds remaining in the life of this credential

     * element. A return value of {@link #INDEFINITE_LIFETIME

     * INDEFINITE_LIFETIME} indicates that the credential element does not

     * expire.  A return value of 0 indicates that the credential element is

     * already expired.

     *

     * @param mech the Oid of the mechanism whose intiator credential element

     * should be queried.

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#BAD_MECH GSSException.BAD_MECH},

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public int getRemainingInitLifetime(Oid mech) throws GSSException;

    /**

     * Returns the lifetime in seconds for the credential to remain capable

     * of accepting security contexts using the specified mechanism. This

     * method queries the acceptor credential element that belongs to the

     * specified mechanism.

     *

     * @return the number of seconds remaining in the life of this credential

     * element. A return value of {@link #INDEFINITE_LIFETIME

     * INDEFINITE_LIFETIME} indicates that the credential element does not

     * expire.  A return value of 0 indicates that the credential element is

     * already expired.

     *

     * @param mech the Oid of the mechanism whose acceptor credential element

     * should be queried.

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#BAD_MECH GSSException.BAD_MECH},

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public int getRemainingAcceptLifetime(Oid mech) throws GSSException;

    /**

     * Returns the credential usage mode. In other words, it

     * tells us if this credential can be used for initiating or accepting

     * security contexts. It does not tell us which mechanism(s) has to be

     * used in order to do so. It is expected that an application will allow

     * the GSS-API to pick a default mechanism after calling this method.

     *

     * @return The return value will be one of {@link #INITIATE_ONLY

     * INITIATE_ONLY}, {@link #ACCEPT_ONLY ACCEPT_ONLY}, and {@link

     * #INITIATE_AND_ACCEPT INITIATE_AND_ACCEPT}.

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public int getUsage() throws GSSException;

    /**

     * Returns the credential usage mode for a specific mechanism. In other

     * words, it tells us if this credential can be used

     * for initiating or accepting security contexts with a given underlying

     * mechanism.

     *

     * @return The return value will be one of {@link #INITIATE_ONLY

     * INITIATE_ONLY}, {@link #ACCEPT_ONLY ACCEPT_ONLY}, and {@link

     * #INITIATE_AND_ACCEPT INITIATE_AND_ACCEPT}.

     * @param mech the Oid of the mechanism whose credentials usage mode is

     * to be determined.

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#BAD_MECH GSSException.BAD_MECH},

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public int getUsage(Oid mech) throws GSSException;

    /**

     * Returns a list of mechanisms supported by this credential. It does

     * not tell us which ones can be used to initiate

     * contexts and which ones can be used to accept contexts. The

     * application must call the {@link #getUsage(Oid) getUsage} method with

     * each of the returned Oid's to determine the possible modes of

     * usage.

     *

     * @return an array of Oid's corresponding to the supported mechanisms.

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public Oid[] getMechs() throws GSSException;

    /**

     * Adds a mechanism specific credential-element to an existing

     * credential.  This method allows the construction of credentials, one

     * mechanism at a time.<p>

     *

     * This routine is envisioned to be used mainly by context acceptors

     * during the creation of acceptor credentials which are to be used

     * with a variety of clients using different security mechanisms.<p>

     *

     * This routine adds the new credential element "in-place".  To add the

     * element in a new credential, first call <code>clone</code> to obtain a

     * copy of this credential, then call its <code>add</code> method.<p>

     *

     * As always, GSS-API implementations must impose a local access-control

     * policy on callers to prevent unauthorized callers from acquiring

     * credentials to which they are not entitled.

     *

     * Non-default values for initLifetime and acceptLifetime cannot always

     * be honored by the underlying mechanisms, thus callers should be

     * prepared to call {@link #getRemainingInitLifetime(Oid)

     * getRemainingInitLifetime} and {@link #getRemainingAcceptLifetime(Oid)

     * getRemainingAcceptLifetime} on the credential.

     *

     * @param name the name of the principal for whom this credential is to

     * be acquired.  Use <code>null</code> to specify the default

     * principal.

     * @param initLifetime the number of seconds that the credential element

     * should remain valid for initiating of security contexts. Use {@link

     * GSSCredential#INDEFINITE_LIFETIME GSSCredential.INDEFINITE_LIFETIME}

     * to request that the credentials have the maximum permitted lifetime

     * for this.  Use {@link GSSCredential#DEFAULT_LIFETIME

     * GSSCredential.DEFAULT_LIFETIME} to request default credential lifetime

     * for this.

     * @param acceptLifetime the number of seconds that the credential

     * element should remain valid for accepting security contexts. Use {@link

     * GSSCredential#INDEFINITE_LIFETIME GSSCredential.INDEFINITE_LIFETIME}

     * to request that the credentials have the maximum permitted lifetime

     * for this.  Use {@link GSSCredential#DEFAULT_LIFETIME

     * GSSCredential.DEFAULT_LIFETIME} to request default credential lifetime

     * for this.

     * @param mech the mechanism over which the credential is to be acquired.

     * @param usage the usage mode that this credential

     * element should add to the credential. The value

     * of this parameter must be one of:

     * {@link #INITIATE_AND_ACCEPT INITIATE_AND_ACCEPT},

     * {@link #ACCEPT_ONLY ACCEPT_ONLY}, and

     * {@link #INITIATE_ONLY INITIATE_ONLY}.

     *

     * @throws GSSException containing the following

     * major error codes:

     *         {@link GSSException#DUPLICATE_ELEMENT

     *                          GSSException.DUPLICATE_ELEMENT},

     *         {@link GSSException#BAD_MECH GSSException.BAD_MECH},

     *         {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},

     *         {@link GSSException#NO_CRED GSSException.NO_CRED},

     *         {@link GSSException#CREDENTIALS_EXPIRED

     *                                  GSSException.CREDENTIALS_EXPIRED},

     *         {@link GSSException#FAILURE GSSException.FAILURE}

     */

    public void add(GSSName name, int initLifetime, int acceptLifetime,

                    Oid mech, int usage) throws GSSException;

    /**

     * Tests if this GSSCredential asserts the same entity as the supplied

     * object.  The two credentials must be acquired over the same

     * mechanisms and must refer to the same principal.

     *

     * @return <code>true</code> if the two GSSCredentials assert the same

     * entity; <code>false</code> otherwise.

     * @param another another GSSCredential for comparison to this one

     */

    public boolean equals(Object another);

    /**

     * Returns a hashcode value for this GSSCredential.

     *

     * @return a hashCode value

     */

    public int hashCode();

}