001/*
002 * nimbus-jose-jwt
003 *
004 * Copyright 2012-2016, Connect2id Ltd.
005 *
006 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use
007 * this file except in compliance with the License. You may obtain a copy of the
008 * License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software distributed
013 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
014 * CONDITIONS OF ANY KIND, either express or implied. See the License for the
015 * specific language governing permissions and limitations under the License.
016 */
017
018package com.nimbusds.jose.proc;
019
020
021import java.security.Key;
022import java.util.List;
023
024import com.nimbusds.jose.JWSHeader;
025import com.nimbusds.jose.KeySourceException;
026
027
028/**
029 * Interface for selecting key candidates for verifying a JSON Web Signature
030 * (JWS) object. Applications should utilise this interface or a similar
031 * framework to determine whether a received JWS object (or signed JWT) is
032 * eligible for {@link com.nimbusds.jose.JWSVerifier verification} and further
033 * processing.
034 *
035 * <p>The interface supports keys selection based on:
036 *
037 * <ul>
038 *     <li>Recognised header parameters referencing the key (e.g. {@code kid},
039 *         {@code x5t}).
040 *     <li>Additional {@link SecurityContext}, if required and set by the
041 *         application (e.g. endpoint where the JWS object was received).
042 * </ul>
043 *
044 * <p>See JSON Web Signature (JWS), Appendix D. Notes on Key Selection for
045 * suggestions.
046 *
047 * <p>For a key selector for signed JWTs that also uses the claims set (e.g.
048 * issuer ({@code iss}) claim) see
049 * {@link com.nimbusds.jwt.proc.JWTClaimsSetAwareJWSKeySelector}.
050 *
051 * <p>Possible key types:
052 *
053 * <ul>
054 *     <li>{@link javax.crypto.SecretKey} for HMAC keys.
055 *     <li>{@link java.security.interfaces.RSAPublicKey} public RSA keys.
056 *     <li>{@link java.security.interfaces.ECPublicKey} public EC keys.
057 * </ul>
058 *
059 * @author Vladimir Dzhuvinov
060 * @version 2016-06-21
061 */
062public interface JWSKeySelector<C extends SecurityContext>  {
063
064
065        /**
066         * Selects key candidates for verifying a JWS object.
067         *
068         * @param header  The header of the JWS object. Must not be
069         *                {@code null}.
070         * @param context Optional context of the JWS object, {@code null} if
071         *                not required.
072         *
073         * @return The key candidates in trial order, empty list if none.
074         *
075         * @throws KeySourceException If a key sourcing exception is
076         *                            encountered, e.g. on remote JWK
077         *                            retrieval.
078         */
079        List<? extends Key> selectJWSKeys(final JWSHeader header, final C context)
080                throws KeySourceException;
081}