1 /**
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.wss4j.common.derivedKey;
20
21 import java.nio.charset.StandardCharsets;
22
23 import org.apache.wss4j.common.ext.WSSecurityException;
24
25 public final class DerivedKeyUtils {
26
27 private DerivedKeyUtils() {
28 // complete
29 }
30
31 /**
32 * Derive a key from this DerivedKeyToken instance
33 *
34 * @param length
35 * @param secret
36 * @throws org.apache.wss4j.stax.wss.ext.WSSecurityException
37 *
38 */
39 public static byte[] deriveKey(String algorithm, String label, int length, byte[] secret, byte[] nonce, int offset)
40 throws WSSecurityException {
41 DerivationAlgorithm algo = AlgoFactory.getInstance(algorithm);
42 byte[] labelBytes;
43 if (label == null || label.length() == 0) {
44 String defaultLabel = ConversationConstants.DEFAULT_LABEL + ConversationConstants.DEFAULT_LABEL;
45 labelBytes = defaultLabel.getBytes(StandardCharsets.UTF_8);
46 } else {
47 labelBytes = label.getBytes(StandardCharsets.UTF_8);
48 }
49
50 byte[] seed = new byte[labelBytes.length + nonce.length];
51 System.arraycopy(labelBytes, 0, seed, 0, labelBytes.length);
52 System.arraycopy(nonce, 0, seed, labelBytes.length, nonce.length);
53
54 long keyLength = length;
55 if (keyLength <= 0) {
56 keyLength = 32L;
57 }
58 return algo.createKey(secret, seed, offset, keyLength);
59 }
60 }