/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.cxf.rs.security.jose.jwe;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.cxf.rs.security.jose.jwa.AlgorithmUtils;
import org.apache.cxf.rs.security.jose.jwa.ContentAlgorithm;
import org.apache.cxf.rt.security.crypto.CryptoUtils;
public abstract class AbstractContentEncryptionAlgorithm extends AbstractContentEncryptionCipherProperties
implements ContentEncryptionProvider {
private static final int DEFAULT_IV_SIZE = 128;
private byte[] cek;
private byte[] iv;
private AtomicInteger providedIvUsageCount;
private boolean generateCekOnce;
protected AbstractContentEncryptionAlgorithm(ContentAlgorithm algo, boolean generateCekOnce) {
super(algo);
this.generateCekOnce = generateCekOnce;
}
protected AbstractContentEncryptionAlgorithm(byte[] cek, byte[] iv, ContentAlgorithm algo) {
super(algo);
this.cek = cek;
this.iv = iv;
if (iv != null && iv.length > 0) {
providedIvUsageCount = new AtomicInteger();
}
}
public byte[] getContentEncryptionKey(JweHeaders headers) {
byte[] theCek = null;
if (cek == null) {
String algoJava = getAlgorithm().getJavaName();
theCek = CryptoUtils.getSecretKey(AlgorithmUtils.stripAlgoProperties(algoJava),
getContentEncryptionKeySize(headers)).getEncoded();
if (generateCekOnce) {
synchronized (this) {
cek = theCek;
}
}
} else {
theCek = cek;
}
return theCek;
}
public byte[] getInitVector() {
if (iv == null) {
return CryptoUtils.generateSecureRandomBytes(getIvSize() / 8);
} else if (iv.length > 0 && providedIvUsageCount.addAndGet(1) > 1) {
LOG.warning("Custom IV is recommended to be used once");
throw new JweException(JweException.Error.CUSTOM_IV_REUSED);
} else {
return iv;
}
}
protected int getContentEncryptionKeySize(JweHeaders headers) {
return getAlgorithm().getKeySizeBits();
}
protected int getIvSize() {
return DEFAULT_IV_SIZE;
}
}