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 javax.crypto.SecretKey; 022 023import com.nimbusds.jose.*; 024import com.nimbusds.jose.crypto.impl.*; 025import com.nimbusds.jose.util.Base64URL; 026import com.nimbusds.jose.util.StandardCharset; 027import net.jcip.annotations.ThreadSafe; 028 029 030/** 031 * Password-based encrypter of {@link com.nimbusds.jose.JWEObject JWE objects}. 032 * Expects a password. 033 * 034 * <p>See RFC 7518 035 * <a href="https://tools.ietf.org/html/rfc7518#section-4.8">section 4.8</a> 036 * for more information. 037 * 038 * <p>This class is thread-safe. 039 * 040 * <p>Supports the following key management algorithms: 041 * 042 * <ul> 043 * <li>{@link com.nimbusds.jose.JWEAlgorithm#PBES2_HS256_A128KW} 044 * <li>{@link com.nimbusds.jose.JWEAlgorithm#PBES2_HS384_A192KW} 045 * <li>{@link com.nimbusds.jose.JWEAlgorithm#PBES2_HS512_A256KW} 046 * </ul> 047 * 048 * <p>Supports the following content encryption algorithms: 049 * 050 * <ul> 051 * <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256} 052 * <li>{@link com.nimbusds.jose.EncryptionMethod#A192CBC_HS384} 053 * <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512} 054 * <li>{@link com.nimbusds.jose.EncryptionMethod#A128GCM} 055 * <li>{@link com.nimbusds.jose.EncryptionMethod#A192GCM} 056 * <li>{@link com.nimbusds.jose.EncryptionMethod#A256GCM} 057 * <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256_DEPRECATED} 058 * <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512_DEPRECATED} 059 * </ul> 060 * 061 * @author Vladimir Dzhuvinov 062 * @version 2016-07-26 063 */ 064@ThreadSafe 065public class PasswordBasedEncrypter extends PasswordBasedCryptoProvider implements JWEEncrypter { 066 067 068 /** 069 * The minimum salt length (8 bytes). 070 */ 071 public static final int MIN_SALT_LENGTH = 8; 072 073 074 /** 075 * The cryptographic salt length, in bytes. 076 */ 077 private final int saltLength; 078 079 080 /** 081 * The minimum recommended iteration count (1000). 082 */ 083 public static final int MIN_RECOMMENDED_ITERATION_COUNT = 1000; 084 085 086 /** 087 * The iteration count. 088 */ 089 private final int iterationCount; 090 091 092 /** 093 * Creates a new password-based encrypter. 094 * 095 * @param password The password bytes. Must not be empty or 096 * {@code null}. 097 * @param saltLength The length of the generated cryptographic 098 * salts, in bytes. Must be at least 8 bytes. 099 * @param iterationCount The pseudo-random function (PRF) iteration 100 * count. Must be at least 1000. 101 */ 102 public PasswordBasedEncrypter(final byte[] password, 103 final int saltLength, 104 final int iterationCount) { 105 106 super(password); 107 108 if (saltLength < MIN_SALT_LENGTH) { 109 throw new IllegalArgumentException("The minimum salt length (p2s) is " + MIN_SALT_LENGTH + " bytes"); 110 } 111 112 this.saltLength = saltLength; 113 114 if (iterationCount < MIN_RECOMMENDED_ITERATION_COUNT) { 115 throw new IllegalArgumentException("The minimum recommended iteration count (p2c) is " + MIN_RECOMMENDED_ITERATION_COUNT); 116 } 117 118 this.iterationCount = iterationCount; 119 } 120 121 122 /** 123 * Creates a new password-based encrypter. 124 * 125 * @param password The password, as a UTF-8 encoded string. Must 126 * not be empty or {@code null}. 127 * @param saltLength The length of the generated cryptographic 128 * salts, in bytes. Must be at least 8 bytes. 129 * @param iterationCount The pseudo-random function (PRF) iteration 130 * count. Must be at least 1000. 131 */ 132 public PasswordBasedEncrypter(final String password, 133 final int saltLength, 134 final int iterationCount) { 135 136 this(password.getBytes(StandardCharset.UTF_8), saltLength, iterationCount); 137 } 138 139 140 @Override 141 public JWECryptoParts encrypt(final JWEHeader header, final byte[] clearText) 142 throws JOSEException { 143 144 final JWEAlgorithm alg = header.getAlgorithm(); 145 final EncryptionMethod enc = header.getEncryptionMethod(); 146 147 final byte[] salt = new byte[saltLength]; 148 getJCAContext().getSecureRandom().nextBytes(salt); 149 final byte[] formattedSalt = PBKDF2.formatSalt(alg, salt); 150 final PRFParams prfParams = PRFParams.resolve(alg, getJCAContext().getMACProvider()); 151 final SecretKey psKey = PBKDF2.deriveKey(getPassword(), formattedSalt, iterationCount, prfParams); 152 153 // We need to work on the header 154 final JWEHeader updatedHeader = new JWEHeader.Builder(header). 155 pbes2Salt(Base64URL.encode(salt)). 156 pbes2Count(iterationCount). 157 build(); 158 159 final SecretKey cek = ContentCryptoProvider.generateCEK(enc, getJCAContext().getSecureRandom()); 160 161 // The second JWE part 162 final Base64URL encryptedKey = Base64URL.encode(AESKW.wrapCEK(cek, psKey, getJCAContext().getKeyEncryptionProvider())); 163 164 return ContentCryptoProvider.encrypt(updatedHeader, clearText, cek, encryptedKey, getJCAContext()); 165 } 166 167 168 /** 169 * Returns the length of the generated cryptographic salts. 170 * 171 * @return The length of the generated cryptographic salts, in bytes. 172 */ 173 public int getSaltLength() { 174 175 return saltLength; 176 } 177 178 179 /** 180 * Returns the pseudo-random function (PRF) iteration count. 181 * 182 * @return The iteration count. 183 */ 184 public int getIterationCount() { 185 186 return iterationCount; 187 } 188}