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.crypto;
019
020
021import java.security.interfaces.RSAPublicKey;
022import javax.crypto.SecretKey;
023
024import com.nimbusds.jose.crypto.impl.*;
025import net.jcip.annotations.ThreadSafe;
026
027import com.nimbusds.jose.EncryptionMethod;
028import com.nimbusds.jose.JOSEException;
029import com.nimbusds.jose.JWEAlgorithm;
030import com.nimbusds.jose.JWECryptoParts;
031import com.nimbusds.jose.JWEEncrypter;
032import com.nimbusds.jose.JWEHeader;
033import com.nimbusds.jose.jwk.RSAKey;
034import com.nimbusds.jose.util.Base64URL;
035
036
037/**
038 * RSA encrypter of {@link com.nimbusds.jose.JWEObject JWE objects}. Expects a
039 * public RSA key.
040 *
041 * <p>Encrypts the plain text with a generated AES key (the Content Encryption
042 * Key) according to the specified JOSE encryption method, then encrypts the
043 * CEK with the public RSA key and returns it alongside the IV, cipher text and
044 * authentication tag. See RFC 7518, sections
045 * <a href="https://tools.ietf.org/html/rfc7518#section-4.2">4.2</a> and
046 * <a href="https://tools.ietf.org/html/rfc7518#section-4.3">4.3</a> for more
047 * information.
048 *
049 * <p>This class is thread-safe.
050 *
051 * <p>Supports the following key management algorithms:
052 *
053 * <ul>
054 *     <li>{@link com.nimbusds.jose.JWEAlgorithm#RSA_OAEP_256}
055 *     <li>{@link com.nimbusds.jose.JWEAlgorithm#RSA_OAEP} (deprecated)
056 *     <li>{@link com.nimbusds.jose.JWEAlgorithm#RSA1_5} (deprecated)
057 * </ul>
058 *
059 * <p>Supports the following content encryption algorithms:
060 *
061 * <ul>
062 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256}
063 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A192CBC_HS384}
064 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512}
065 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A128GCM}
066 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A192GCM}
067 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A256GCM}
068 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256_DEPRECATED}
069 *     <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512_DEPRECATED}
070 *     <li>{@link com.nimbusds.jose.EncryptionMethod#XC20P}
071 * </ul>
072 *
073 * @author David Ortiz
074 * @author Vladimir Dzhuvinov
075 * @author Jun Yu
076 * @version 2018-07-17
077 */
078@ThreadSafe
079public class RSAEncrypter extends RSACryptoProvider implements JWEEncrypter {
080
081
082        /**
083         * The public RSA key.
084         */
085        private final RSAPublicKey publicKey;
086
087        
088        /**
089         * The externally supplied AES content encryption key (CEK) to use,
090         * {@code null} to generate a CEK for each JWE.
091         */
092        private final SecretKey contentEncryptionKey;
093
094        
095        /**
096         * Creates a new RSA encrypter.
097         *
098         * @param publicKey The public RSA key. Must not be {@code null}.
099         */
100        public RSAEncrypter(final RSAPublicKey publicKey) {
101
102                this(publicKey, null);
103        }
104
105
106        /**
107         * Creates a new RSA encrypter.
108         *
109         *  @param rsaJWK The RSA JSON Web Key (JWK). Must not be {@code null}.
110         *
111         * @throws JOSEException If the RSA JWK extraction failed.
112         */
113        public RSAEncrypter(final RSAKey rsaJWK)
114                throws JOSEException {
115
116                this(rsaJWK.toRSAPublicKey());
117        }
118
119
120        /**
121         * Creates a new RSA encrypter with an optionally specified content
122         * encryption key (CEK).
123         *
124         * @param publicKey            The public RSA key. Must not be
125         *                             {@code null}.
126         * @param contentEncryptionKey The content encryption key (CEK) to use.
127         *                             If specified its algorithm must be "AES"
128         *                             and its length must match the expected
129         *                             for the JWE encryption method ("enc").
130         *                             If {@code null} a CEK will be generated
131         *                             for each JWE.
132         */
133        public RSAEncrypter(final RSAPublicKey publicKey, final SecretKey contentEncryptionKey) {
134                
135                if (publicKey == null) {
136                        throw new IllegalArgumentException("The public RSA key must not be null");
137                }
138                this.publicKey = publicKey;
139
140                if (contentEncryptionKey != null) {
141                        if (contentEncryptionKey.getAlgorithm() == null || !contentEncryptionKey.getAlgorithm().equals("AES")) {
142                                throw new IllegalArgumentException("The algorithm of the content encryption key (CEK) must be AES");
143                        } else {
144                                this.contentEncryptionKey = contentEncryptionKey;
145                        }
146                } else {
147                        this.contentEncryptionKey = null;
148                }
149        }
150        
151        
152        /**
153         * Gets the public RSA key.
154         *
155         * @return The public RSA key.
156         */
157        public RSAPublicKey getPublicKey() {
158                
159                return publicKey;
160        }
161
162
163        @Override
164        public JWECryptoParts encrypt(final JWEHeader header, final byte[] clearText)
165                throws JOSEException {
166
167                final JWEAlgorithm alg = header.getAlgorithm();
168                final EncryptionMethod enc = header.getEncryptionMethod();
169
170                // Generate and encrypt the CEK according to the enc method
171                final SecretKey cek;
172                if (contentEncryptionKey != null) {
173                        // Use externally supplied CEK
174                        cek = contentEncryptionKey;
175                } else {
176                        // Generate and encrypt the CEK according to the enc method
177                        cek = ContentCryptoProvider.generateCEK(enc, getJCAContext().getSecureRandom());
178                }
179
180                final Base64URL encryptedKey; // The second JWE part
181
182                if (alg.equals(JWEAlgorithm.RSA1_5)) {
183
184                        encryptedKey = Base64URL.encode(RSA1_5.encryptCEK(publicKey, cek, getJCAContext().getKeyEncryptionProvider()));
185
186                } else if (alg.equals(JWEAlgorithm.RSA_OAEP)) {
187
188                        encryptedKey = Base64URL.encode(RSA_OAEP.encryptCEK(publicKey, cek, getJCAContext().getKeyEncryptionProvider()));
189
190                } else if (alg.equals(JWEAlgorithm.RSA_OAEP_256)) {
191                        
192                        encryptedKey = Base64URL.encode(RSA_OAEP_256.encryptCEK(publicKey, cek, getJCAContext().getKeyEncryptionProvider()));
193                        
194                } else {
195
196                        throw new JOSEException(AlgorithmSupportMessage.unsupportedJWEAlgorithm(alg, SUPPORTED_ALGORITHMS));
197                }
198
199                return ContentCryptoProvider.encrypt(header, clearText, cek, encryptedKey, getJCAContext());
200        }
201}