/*
* Copyright 2014 Red Hat, Inc.
*
* Licensed 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 io.nodyn.crypto;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.macs.HMac;
import org.bouncycastle.crypto.params.KeyParameter;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
public class Hmac {
private final HMac hmac;
public Hmac(Digest digest, ByteBuf key) throws InvalidKeyException {
this.hmac = new HMac( digest );
computeKey(key);
}
private void computeKey(ByteBuf key) throws InvalidKeyException {
byte[] keyBytes = new byte[ key.readableBytes() ];
key.readBytes( keyBytes );
SecretKeySpec secretKey = new SecretKeySpec(keyBytes, this.hmac.getUnderlyingDigest().getAlgorithmName() );
KeyParameter param = new KeyParameter(secretKey.getEncoded());
this.hmac.init(param);
}
public void update(ByteBuf buf) {
byte[] bytes = new byte[buf.readableBytes()];
buf.getBytes(buf.readerIndex(), bytes);
this.hmac.update(bytes, 0, bytes.length);
}
public ByteBuf digest() throws NoSuchAlgorithmException {
byte[] digestBytes = new byte[this.hmac.getMacSize()];
this.hmac.doFinal(digestBytes, 0);
return Unpooled.wrappedBuffer(digestBytes);
}
}