001/*
002 * nimbus-jose-jwt
003 *
004 * Copyright 2012-2016, Connect2id Ltd and contributors.
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.crypto.impl;
019
020
021import java.security.Provider;
022import java.util.Objects;
023
024import com.nimbusds.jose.JOSEException;
025import com.nimbusds.jose.JWEAlgorithm;
026import net.jcip.annotations.Immutable;
027
028
029/**
030 * Pseudo-Random Function (PRF) parameters, intended for use in the Password-
031 * Based Key Derivation Function 2 (PBKDF2).
032 *
033 * @author Vladimir Dzhuvinov
034 * @version 2024-09-10
035 */
036@Immutable
037public final class PRFParams {
038
039
040        /**
041         * The JCA MAC algorithm name.
042         */
043        private final String jcaMacAlg;
044
045
046        /**
047         * The JCA MAC provider, {@code null} to use the default one.
048         */
049        private final Provider macProvider;
050
051
052        /**
053         * The byte length of the key to derive.
054         */
055        private final int dkLen;
056
057
058        /**
059         * Creates a new pseudo-random function parameters instance.
060         *
061         * @param jcaMacAlg   The JCA MAC algorithm name. Must not be
062         *                    {@code null}.
063         * @param macProvider The JCA MAC provider, {@code null} to use the
064         *                    default one.
065         * @param dkLen       The byte length of the key to derive.
066
067         */
068        public PRFParams(final String jcaMacAlg, final Provider macProvider, final int dkLen) {
069                this.jcaMacAlg = Objects.requireNonNull(jcaMacAlg);
070                this.macProvider = macProvider;
071                this.dkLen = dkLen;
072        }
073
074
075        /**
076         * Returns the JCA MAC algorithm name.
077         *
078         * @return The JCA MAC algorithm name.
079         */
080        public String getMACAlgorithm() {
081
082                return jcaMacAlg;
083        }
084
085
086        /**
087         * Returns the JCA MAC provider.
088         *
089         * @return The JCA MAC provider, {@code null} to use the default one.
090         */
091        public Provider getMacProvider() {
092
093                return macProvider;
094        }
095
096
097        /**
098         * Returns the byte length of the key to derive.
099         *
100         * @return The byte length of the key to derive.
101         */
102        public int getDerivedKeyByteLength() {
103
104                return dkLen;
105        }
106
107
108        /**
109         * Resolves the Pseudo-Random Function (PRF) parameters for the
110         * specified PBES2 JWE algorithm.
111         *
112         * @param alg         The JWE algorithm. Must be supported and not
113         *                    {@code null}.
114         * @param macProvider The specific MAC JCA provider, {@code null} to
115         *                    use the default one.
116         *
117         * @return The PRF parameters.
118         *
119         * @throws JOSEException If the JWE algorithm is not supported.
120         */
121        public static PRFParams resolve(final JWEAlgorithm alg, final Provider macProvider)
122                throws JOSEException {
123
124                final String jcaMagAlg;
125                final int dkLen;
126
127                if (JWEAlgorithm.PBES2_HS256_A128KW.equals(alg)) {
128                        jcaMagAlg = "HmacSHA256";
129                        dkLen = 16;
130                } else if (JWEAlgorithm.PBES2_HS384_A192KW.equals(alg)) {
131                        jcaMagAlg = "HmacSHA384";
132                        dkLen = 24;
133                } else if (JWEAlgorithm.PBES2_HS512_A256KW.equals(alg)) {
134                        jcaMagAlg = "HmacSHA512";
135                        dkLen = 32;
136                } else {
137                        throw new JOSEException(AlgorithmSupportMessage.unsupportedJWEAlgorithm(
138                                alg,
139                                PasswordBasedCryptoProvider.SUPPORTED_ALGORITHMS));
140                }
141
142                return new PRFParams(jcaMagAlg, macProvider, dkLen);
143        }
144}