/*
* 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.sshd.common.mac;
import javax.crypto.spec.SecretKeySpec;
import org.apache.sshd.common.Mac;
import org.apache.sshd.common.util.SecurityUtils;
/**
* Base class for <code>Mac</code> implementations based on the JCE provider.
*
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public class BaseMac implements Mac {
private final String algorithm;
private final int defbsize;
private final int bsize;
private final byte[] tmp;
private javax.crypto.Mac mac;
public BaseMac(String algorithm, int bsize, int defbsize) {
this.algorithm = algorithm;
this.bsize = bsize;
this.defbsize = defbsize;
this.tmp = new byte[defbsize];
}
public int getBlockSize() {
return bsize;
}
public void init(byte[] key) throws Exception {
if (key.length > defbsize) {
byte[] tmp = new byte[defbsize];
System.arraycopy(key, 0, tmp, 0, defbsize);
key = tmp;
}
SecretKeySpec skey = new SecretKeySpec(key, algorithm);
mac = SecurityUtils.getMac(algorithm);
mac.init(skey);
}
public void updateUInt(long i) {
tmp[0] = (byte) (i >>> 24);
tmp[1] = (byte) (i >>> 16);
tmp[2] = (byte) (i >>> 8);
tmp[3] = (byte) i;
update(tmp, 0, 4);
}
public void update(byte foo[], int s, int l) {
mac.update(foo, s, l);
}
public void doFinal(byte[] buf, int offset) throws Exception {
if (bsize != defbsize) {
mac.doFinal(tmp, 0);
System.arraycopy(tmp, 0, buf, offset, bsize);
} else {
mac.doFinal(buf, offset);
}
}
}