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* 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
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package org.apache.cayenne.crypto.transformer.bytes;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import javax.crypto.Mac;
import org.apache.cayenne.CayenneRuntimeException;
/**
* Actual authentication code generation logic that is used
* by both {@link HmacEncryptor} and {@link HmacDecryptor}.
*
* @since 4.0
*/
abstract class HmacCreator {
/**
* Default algorithm for authentication code creation.
*/
public static final String DEFAULT_HMAC_ALGORITHM = "HmacSHA256";
private Header header;
private Mac mac;
HmacCreator(Header header, Key key) {
this.header = header;
try {
// Currently algorithm is hardcoded, but can be easily transformed into configurable parameter
mac = Mac.getInstance(DEFAULT_HMAC_ALGORITHM);
mac.init(key);
} catch (NoSuchAlgorithmException nsae) {
throw new CayenneRuntimeException("Algorithm %s not supported for HMAC generation", nsae, DEFAULT_HMAC_ALGORITHM);
} catch (InvalidKeyException ike) {
throw new CayenneRuntimeException("Invalid key for HMAC generation", ike);
}
}
byte[] createHmac(byte[] input) {
byte[] rawHeader = new byte[header.size()];
header.store(rawHeader, 0, header.getFlags());
mac.update(rawHeader);
return mac.doFinal(input);
}
}