javax.crypto.MacSpi Maven / Gradle / Ivy
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
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*
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package javax.crypto;
import java.security.*;
import java.security.spec.*;
import java.nio.ByteBuffer;
/**
* This class defines the Service Provider Interface (SPI)
* for the Mac class.
* All the abstract methods in this class must be implemented by each
* cryptographic service provider who wishes to supply the implementation
* of a particular MAC algorithm.
*
* Implementations are free to implement the Cloneable interface.
*
* @author Jan Luehe
*
* @since 1.4
*/
public abstract class MacSpi {
/**
* Constructor for subclasses to call.
*/
public MacSpi() {}
/**
* Returns the length of the MAC in bytes.
*
* @return the MAC length in bytes.
*/
protected abstract int engineGetMacLength();
/**
* Initializes the MAC with the given (secret) key and algorithm
* parameters.
*
* @param key the (secret) key.
* @param params the algorithm parameters.
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this MAC.
* @exception InvalidAlgorithmParameterException if the given algorithm
* parameters are inappropriate for this MAC.
*/
protected abstract void engineInit(Key key,
AlgorithmParameterSpec params)
throws InvalidKeyException, InvalidAlgorithmParameterException ;
/**
* Processes the given byte.
*
* @param input the input byte to be processed.
*/
protected abstract void engineUpdate(byte input);
/**
* Processes the first len bytes in input,
* starting at offset inclusive.
*
* @param input the input buffer.
* @param offset the offset in input where the input starts.
* @param len the number of bytes to process.
*/
protected abstract void engineUpdate(byte[] input, int offset, int len);
/**
* Processes input.remaining() bytes in the ByteBuffer
* input, starting at input.position().
* Upon return, the buffer's position will be equal to its limit;
* its limit will not have changed.
*
*
Subclasses should consider overriding this method if they can
* process ByteBuffers more efficiently than byte arrays.
*
* @param input the ByteBuffer
* @since 1.5
*/
protected void engineUpdate(ByteBuffer input) {
if (input.hasRemaining() == false) {
return;
}
if (input.hasArray()) {
byte[] b = input.array();
int ofs = input.arrayOffset();
int pos = input.position();
int lim = input.limit();
engineUpdate(b, ofs + pos, lim - pos);
input.position(lim);
} else {
int len = input.remaining();
byte[] b = new byte[CipherSpi.getTempArraySize(len)];
while (len > 0) {
int chunk = Math.min(len, b.length);
input.get(b, 0, chunk);
engineUpdate(b, 0, chunk);
len -= chunk;
}
}
}
/**
* Completes the MAC computation and resets the MAC for further use,
* maintaining the secret key that the MAC was initialized with.
*
* @return the MAC result.
*/
protected abstract byte[] engineDoFinal();
/**
* Resets the MAC for further use, maintaining the secret key that the
* MAC was initialized with.
*/
protected abstract void engineReset();
/**
* Returns a clone if the implementation is cloneable.
*
* @return a clone if the implementation is cloneable.
*
* @exception CloneNotSupportedException if this is called
* on an implementation that does not support Cloneable.
*/
public Object clone() throws CloneNotSupportedException {
if (this instanceof Cloneable) {
return super.clone();
} else {
throw new CloneNotSupportedException();
}
}
}