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Java > Open Source Codes > org > jmanage > core > crypto > EncryptedKey


1 /**
2  * Copyright 2004-2005 jManage.org
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.jmanage.core.crypto;
17
18 import javax.crypto.SecretKey;
19 import javax.crypto.SecretKeyFactory;
20 import javax.crypto.Cipher;
21 import javax.crypto.KeyGenerator;
22 import javax.crypto.spec.PBEKeySpec;
23 import javax.crypto.spec.PBEParameterSpec;
24 import javax.crypto.spec.DESedeKeySpec;
25
26 /**
27  *
28  * date: Jul 22, 2004
29  * @author Rakesh Kalra
30  */
31 public class EncryptedKey {
32
33     /* encryption/decryption algorigthm */
34     public static final String JavaDoc CRYPTO_ALGORITHM = "DESede";
35
36     private static final String JavaDoc PBE_ALGORITHM = "PBEWithMD5AndDES";
37
38     /* TripleDES key size */
39     private static final int KEY_SIZE = 112; /* 128 bits (112 effective bits) */
40
41
42
43     /* Salt */
44     private static final byte[] salt = {
45         (byte) 0xd7, (byte) 0x73, (byte) 0x31, (byte) 0x8c,
46         (byte) 0x8e, (byte) 0xb7, (byte) 0xee, (byte) 0x91
47     };
48
49     /* Iteration count */
50     private static final int iteration_count = 1000;
51
52     private SecretKey secretKey;
53     private byte[] encryptedKey;
54
55     public EncryptedKey(char[] password)
56             throws Exception JavaDoc {
57
58         KeyGenerator keyGen = KeyGenerator.getInstance(CRYPTO_ALGORITHM);
59         keyGen.init(KEY_SIZE);
60         SecretKey key = keyGen.generateKey();
61         this.secretKey = key;
62         this.encryptedKey = getEncrypted(secretKey.getEncoded(), password);
63     }
64
65     public EncryptedKey(byte[] encryptedKey, char[] password) {
66
67         this.encryptedKey = encryptedKey;
68         /* get SecretKey from encryptedKey */
69         byte[] key = getDecrypted(encryptedKey, password);
70         try {
71             SecretKeyFactory keyFac = SecretKeyFactory.getInstance(CRYPTO_ALGORITHM);
72             this.secretKey = keyFac.generateSecret(new DESedeKeySpec(key));;
73         } catch (Exception JavaDoc e) {
74             throw new RuntimeException JavaDoc(e);
75         }
76     }
77
78     /**
79      * Re-generates the encryptedKey based on the given password.
80      *
81      * @param password
82      */
83     public void setPassword(char[] password){
84         assert password != null;
85         this.encryptedKey = getEncrypted(secretKey.getEncoded(), password);
86     }
87
88     public SecretKey getSecretKey() {
89         return secretKey;
90     }
91
92     public byte[] get() {
93         return encryptedKey;
94     }
95
96     private static byte[] getEncrypted(byte[] plaintext, char[] password) {
97
98         try {
99             /* Create PBE Cipher */
100             Cipher pbeCipher = getCipher(Cipher.ENCRYPT_MODE, password);
101             /* Encrypt the plaintext */
102             return pbeCipher.doFinal(plaintext);
103         } catch (Exception JavaDoc e) {
104             throw new RuntimeException JavaDoc(e);
105         }
106     }
107
108     private static byte[] getDecrypted(byte[] cyphertext, char[] password){
109
110         try {
111             /* Create PBE Cipher */
112             Cipher cipher = getCipher(Cipher.DECRYPT_MODE, password);
113             /* get the plaintext */
114             return cipher.doFinal(cyphertext);
115         } catch (Exception JavaDoc e) {
116             throw new RuntimeException JavaDoc(e);
117         }
118     }
119
120     private static Cipher getCipher(int mode, char[] password)
121             throws Exception JavaDoc {
122
123         PBEKeySpec pbeKeySpec;
124         PBEParameterSpec pbeParamSpec;
125         SecretKeyFactory keyFac;
126
127         /* Create PBE parameter set */
128         pbeParamSpec = new PBEParameterSpec(salt, iteration_count);
129
130         pbeKeySpec = new PBEKeySpec(password);
131         keyFac = SecretKeyFactory.getInstance(PBE_ALGORITHM);
132         SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
133
134         /* Create PBE Cipher */
135         Cipher pbeCipher = Cipher.getInstance(PBE_ALGORITHM);
136
137         /* Initialize PBE Cipher with key and parameters */
138         pbeCipher.init(mode, pbeKey, pbeParamSpec);
139         return pbeCipher;
140     }
141 }
142
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