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.InvalidAlgorithmParameterException;
022import java.security.NoSuchAlgorithmException;
023import java.security.Provider;
024import java.security.Signature;
025import java.security.spec.MGF1ParameterSpec;
026import java.security.spec.PSSParameterSpec;
027
028import com.nimbusds.jose.JOSEException;
029import com.nimbusds.jose.JWSAlgorithm;
030
031
032/**
033 * RSA-SSA functions and utilities.
034 *
035 * @author Vladimir Dzhuvinov
036 * @version 2021-08-01
037 */
038public class RSASSA {
039
040
041        /**
042         * Returns a signer and verifier for the specified RSASSA-based JSON
043         * Web Algorithm (JWA).
044         *
045         * @param alg The JSON Web Algorithm (JWA). Must be supported and not
046         *            {@code null}.
047         *
048         * @return A signer and verifier instance.
049         *
050         * @throws JOSEException If the algorithm is not supported.
051         */
052        public static Signature getSignerAndVerifier(final JWSAlgorithm alg,
053                                                     final Provider provider)
054                throws JOSEException {
055
056                Signature signature;
057
058                if (alg.equals(JWSAlgorithm.RS256)
059                                && (signature = getSignerAndVerifier("SHA256withRSA", provider)) != null) {
060
061                        return signature;
062
063                } else if (alg.equals(JWSAlgorithm.RS384)
064                                && (signature = getSignerAndVerifier("SHA384withRSA", provider)) != null) {
065
066                        return signature;
067
068                } else if (alg.equals(JWSAlgorithm.RS512)
069                                && (signature = getSignerAndVerifier("SHA512withRSA", provider)) != null) {
070
071                        return signature;
072
073                } else if (alg.equals(JWSAlgorithm.PS256) // JWA mandates salt length equals hash
074                                && (signature = getSignerAndVerifier("RSASSA-PSS", provider, new PSSParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256, 32, 1))) != null) {
075
076                        return signature;
077
078                } else if (alg.equals(JWSAlgorithm.PS256)
079                                && (signature = getSignerAndVerifier("SHA256withRSAandMGF1", provider)) != null) {
080
081                        return signature;
082
083                } else if (alg.equals(JWSAlgorithm.PS384) // JWA mandates salt length equals hash
084                                && (signature = getSignerAndVerifier("RSASSA-PSS", provider, new PSSParameterSpec("SHA-384", "MGF1", MGF1ParameterSpec.SHA384, 48, 1))) != null) {
085
086                        return signature;
087
088                } else if (alg.equals(JWSAlgorithm.PS384)
089                                && (signature = getSignerAndVerifier("SHA384withRSAandMGF1", provider)) != null) {
090
091                        return signature;
092
093                } else if (alg.equals(JWSAlgorithm.PS512) // JWA mandates salt length equals hash
094                                && (signature = getSignerAndVerifier("RSASSA-PSS", provider, new PSSParameterSpec("SHA-512", "MGF1", MGF1ParameterSpec.SHA512, 64, 1))) != null) {
095
096                        return signature;
097
098                } else if (alg.equals(JWSAlgorithm.PS512)
099                                && (signature = getSignerAndVerifier("SHA512withRSAandMGF1", provider)) != null) {
100
101                        return signature;
102
103                }
104
105                throw new JOSEException(AlgorithmSupportMessage.unsupportedJWSAlgorithm(alg, RSASSAProvider.SUPPORTED_ALGORITHMS));
106        }
107
108        private static Signature getSignerAndVerifier(final String jcaAlg, final Provider provider)
109                        throws JOSEException {
110                return getSignerAndVerifier(jcaAlg, provider, null);
111        }
112
113        private static Signature getSignerAndVerifier(final String jcaAlg, final Provider provider, final PSSParameterSpec pssSpec)
114                        throws JOSEException {
115
116                Signature signature;
117                try {
118                        if (provider != null) {
119                                signature = Signature.getInstance(jcaAlg, provider);
120                        } else {
121                                signature = Signature.getInstance(jcaAlg);
122                        }
123                } catch (NoSuchAlgorithmException ignore) {
124                        return null;
125                }
126
127                if (pssSpec != null) {
128                        try {
129                                signature.setParameter(pssSpec);
130                        } catch (InvalidAlgorithmParameterException e) {
131                                throw new JOSEException("Invalid RSASSA-PSS salt length parameter: " + e.getMessage(), e);
132                        }
133                }
134
135                return signature;
136        }
137
138        /**
139         * Prevents public instantiation.
140         */
141        private RSASSA() {
142
143        }
144}