Source code: gnu/javax/crypto/prng/PBKDF2.java
1 /* PBKDF2.java --
2 Copyright (C) 2003, 2006 Free Software Foundation, Inc.
3
4 This file is a part of GNU Classpath.
5
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or (at
9 your option) any later version.
10
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
19 USA
20
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
25
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
37
38
39 package gnu.javax.crypto.prng;
40
41 import gnu.java.security.prng.BasePRNG;
42 import gnu.java.security.prng.LimitReachedException;
43 import gnu.javax.crypto.mac.HMac;
44 import gnu.javax.crypto.mac.IMac;
45
46 import java.io.UnsupportedEncodingException;
47 import java.util.Arrays;
48 import java.util.HashMap;
49 import java.util.Map;
50
51 /**
52 * <p>An implementation of the <i>key derivation function</i> KDF2 from PKCS #5:
53 * Password-Based Cryptography (<b>PBE</b>). This KDF is essentially a way to
54 * transform a password and a salt into a stream of random bytes, which may then
55 * be used to initialize a cipher or a MAC.</p>
56 *
57 * <p>This version uses a MAC as its pseudo-random function, and the password is
58 * used as the key.</p>
59 *
60 * <p>References:</p>
61 * <ol>
62 * <li>B. Kaliski, <a href="http://www.ietf.org/rfc/rfc2898.txt">RFC 2898:
63 * Password-Based Cryptography Specification, Version 2.0</a></li>
64 * </ol>
65 */
66 public class PBKDF2 extends BasePRNG implements Cloneable
67 {
68
69 // Contstants and variables
70 // -------------------------------------------------------------------------
71
72 /**
73 * The bytes fed into the MAC. This is initially the concatenation of the
74 * salt and the block number.
75 */
76 private byte[] in;
77
78 /** The iteration count. */
79 private int iterationCount;
80
81 /** The salt. */
82 private byte[] salt;
83
84 /** The MAC (the pseudo-random function we use). */
85 private IMac mac;
86
87 /** The number of hLen-sized blocks generated. */
88 private long count;
89
90 // Constructor(s)
91 // -------------------------------------------------------------------------
92
93 /**
94 * <p>Creates a new PBKDF2 object. The argument is the MAC that will serve as
95 * the pseudo-random function. The MAC does not need to be initialized.</p>
96 *
97 * @param mac The pseudo-random function.
98 */
99 public PBKDF2(IMac mac)
100 {
101 super("PBKDF2-" + mac.name());
102 this.mac = mac;
103 iterationCount = -1;
104 }
105
106 // Class methods
107 // -------------------------------------------------------------------------
108
109 // Instance methods
110 // -------------------------------------------------------------------------
111
112 public void setup(Map attributes)
113 {
114 Map macAttrib = new HashMap();
115 macAttrib.put(HMac.USE_WITH_PKCS5_V2, Boolean.TRUE);
116
117 byte[] s = (byte[]) attributes.get(IPBE.SALT);
118 if (s == null)
119 {
120 if (salt == null)
121 {
122 throw new IllegalArgumentException("no salt specified");
123 } // Otherwise re-use.
124 }
125 else
126 {
127 salt = s;
128 }
129
130 byte[] macKeyMaterial;
131 char[] password = (char[]) attributes.get(IPBE.PASSWORD);
132 if (password != null)
133 {
134 String encoding = (String) attributes.get(IPBE.PASSWORD_ENCODING);
135 if (encoding == null || encoding.trim().length() == 0)
136 encoding = IPBE.DEFAULT_PASSWORD_ENCODING;
137 else
138 encoding = encoding.trim();
139
140 try
141 {
142 macKeyMaterial = new String(password).getBytes(encoding);
143 }
144 catch (UnsupportedEncodingException uee)
145 {
146 throw new IllegalArgumentException("Unknown or unsupported encoding: "
147 + encoding, uee);
148 }
149 }
150 else
151 macKeyMaterial = (byte[]) attributes.get(IMac.MAC_KEY_MATERIAL);
152
153 if (macKeyMaterial != null)
154 macAttrib.put(IMac.MAC_KEY_MATERIAL, macKeyMaterial);
155 else if (!initialised)
156 throw new IllegalArgumentException("Neither password nor key-material were specified");
157 // otherwise re-use previous password/key-material
158
159 try
160 {
161 mac.init(macAttrib);
162 }
163 catch (Exception x)
164 {
165 throw new IllegalArgumentException(x.getMessage());
166 }
167
168 Integer ic = (Integer) attributes.get(IPBE.ITERATION_COUNT);
169 if (ic != null)
170 {
171 iterationCount = ic.intValue();
172 }
173 if (iterationCount <= 0)
174 {
175 throw new IllegalArgumentException("bad iteration count");
176 }
177
178 count = 0L;
179 buffer = new byte[mac.macSize()];
180 try
181 {
182 fillBlock();
183 // } catch (Exception x) {
184 }
185 catch (LimitReachedException x)
186 {
187 // x.printStackTrace(System.err);
188 throw new Error(x.getMessage());
189 }
190 }
191
192 public void fillBlock() throws LimitReachedException
193 {
194 if (++count > ((1L << 32) - 1))
195 {
196 throw new LimitReachedException();
197 }
198 // for (int i = 0; i < buffer.length; i++) {
199 // buffer[i] = 0;
200 // }
201 Arrays.fill(buffer, (byte) 0x00);
202 int limit = salt.length;
203 // in = new byte[salt.length + 4];
204 in = new byte[limit + 4];
205 System.arraycopy(salt, 0, in, 0, salt.length);
206 // in[salt.length ] = (byte)(count >>> 24);
207 // in[salt.length+1] = (byte)(count >>> 16);
208 // in[salt.length+2] = (byte)(count >>> 8);
209 // in[salt.length+3] = (byte) count;
210 in[limit++] = (byte) (count >>> 24);
211 in[limit++] = (byte) (count >>> 16);
212 in[limit++] = (byte) (count >>> 8);
213 in[limit] = (byte) count;
214 for (int i = 0; i < iterationCount; i++)
215 {
216 mac.reset();
217 mac.update(in, 0, in.length);
218 in = mac.digest();
219 for (int j = 0; j < buffer.length; j++)
220 {
221 buffer[j] ^= in[j];
222 }
223 }
224 }
225 }