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.util.Set; 022import javax.crypto.SecretKey; 023 024import com.nimbusds.jose.*; 025import com.nimbusds.jose.util.Base64URL; 026import com.nimbusds.jose.util.StandardCharset; 027import net.jcip.annotations.ThreadSafe; 028 029 030/** 031 * Password-based decrypter 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 PasswordBasedDecrypter extends PasswordBasedCryptoProvider implements JWEDecrypter, CriticalHeaderParamsAware { 066 067 068 /** 069 * The critical header policy. 070 */ 071 private final CriticalHeaderParamsDeferral critPolicy = new CriticalHeaderParamsDeferral(); 072 073 074 /** 075 * Creates a new password-based decrypter. 076 * 077 * @param password The password bytes. Must not be empty or 078 * {@code null}. 079 */ 080 public PasswordBasedDecrypter(final byte[] password) { 081 082 super(password); 083 } 084 085 086 /** 087 * Creates a new password-based decrypter. 088 * 089 * @param password The password, as a UTF-8 encoded string. Must not be 090 * empty or {@code null}. 091 */ 092 public PasswordBasedDecrypter(final String password) { 093 094 super(password.getBytes(StandardCharset.UTF_8)); 095 } 096 097 098 @Override 099 public Set<String> getProcessedCriticalHeaderParams() { 100 101 return critPolicy.getProcessedCriticalHeaderParams(); 102 } 103 104 105 @Override 106 public Set<String> getDeferredCriticalHeaderParams() { 107 108 return critPolicy.getProcessedCriticalHeaderParams(); 109 } 110 111 112 @Override 113 public byte[] decrypt(final JWEHeader header, 114 final Base64URL encryptedKey, 115 final Base64URL iv, 116 final Base64URL cipherText, 117 final Base64URL authTag) 118 throws JOSEException { 119 120 // Validate required JWE parts 121 if (encryptedKey == null) { 122 throw new JOSEException("Missing JWE encrypted key"); 123 } 124 125 if (iv == null) { 126 throw new JOSEException("Missing JWE initialization vector (IV)"); 127 } 128 129 if (authTag == null) { 130 throw new JOSEException("Missing JWE authentication tag"); 131 } 132 133 if (header.getPBES2Salt() == null) { 134 throw new JOSEException("Missing JWE \"p2s\" header parameter"); 135 } 136 137 final byte[] salt = header.getPBES2Salt().decode(); 138 139 if (header.getPBES2Count() < 1) { 140 throw new JOSEException("Missing JWE \"p2c\" header parameter"); 141 } 142 143 final int iterationCount = header.getPBES2Count(); 144 145 critPolicy.ensureHeaderPasses(header); 146 147 final JWEAlgorithm alg = header.getAlgorithm(); 148 final byte[] formattedSalt = PBKDF2.formatSalt(alg, salt); 149 final PRFParams prfParams = PRFParams.resolve(alg, getJCAContext().getMACProvider()); 150 final SecretKey psKey = PBKDF2.deriveKey(getPassword(), formattedSalt, iterationCount, prfParams); 151 152 final SecretKey cek = AESKW.unwrapCEK(psKey, encryptedKey.decode(), getJCAContext().getKeyEncryptionProvider()); 153 154 return ContentCryptoProvider.decrypt(header, encryptedKey, iv, cipherText, authTag, cek, getJCAContext()); 155 } 156}