Class MacSpi

java.lang.Object
javax.crypto.MacSpi
public abstract class MacSpi extends Object
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.

Since:
1.4

Constructor Summary

Constructor Description
MacSpi()
Constructor for subclasses to call.

Method Summary

Modifier and Type Method Description
Object clone()
Returns a clone if the implementation is cloneable.
protected abstract byte[] engineDoFinal()
Completes the MAC computation and resets the MAC for further use, maintaining the secret key that the MAC was initialized with.
protected abstract int engineGetMacLength()
Returns the length of the MAC in bytes.
protected abstract void engineInit(Key key, AlgorithmParameterSpec params)
Initializes the MAC with the given (secret) key and algorithm parameters.
protected abstract void engineReset()
Resets the MAC for further use, maintaining the secret key that the MAC was initialized with.
protected abstract void engineUpdate(byte input)
Processes the given byte.
protected abstract void engineUpdate(byte[] input, int offset, int len)
Processes the first len bytes in input, starting at offset inclusive.
protected void engineUpdate(ByteBuffer input)
Processes input.remaining() bytes in the ByteBuffer input, starting at input.position().

Methods declared in class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MacSpi

public MacSpi()
Constructor for subclasses to call.

Method Details

engineGetMacLength

protected abstract int engineGetMacLength()
Returns the length of the MAC in bytes.
Returns:
the MAC length in bytes.

engineInit

protected abstract void engineInit(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException
Initializes the MAC with the given (secret) key and algorithm parameters.
Parameters:
key - the (secret) key.
params - the algorithm parameters.
Throws:
InvalidKeyException - if the given key is inappropriate for initializing this MAC.
InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this MAC.

engineUpdate

protected abstract void engineUpdate(byte input)
Processes the given byte.
Parameters:
input - the input byte to be processed.

engineUpdate

protected abstract void engineUpdate(byte[] input, int offset, int len)
Processes the first len bytes in input, starting at offset inclusive.
Parameters:
input - the input buffer.
offset - the offset in input where the input starts.
len - the number of bytes to process.

engineUpdate

protected void engineUpdate(ByteBuffer input)
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.

Parameters:
input - the ByteBuffer
Since:
1.5

engineDoFinal

protected abstract byte[] engineDoFinal()
Completes the MAC computation and resets the MAC for further use, maintaining the secret key that the MAC was initialized with.
Returns:
the MAC result.

engineReset

protected abstract void engineReset()
Resets the MAC for further use, maintaining the secret key that the MAC was initialized with.

clone

public Object clone() throws CloneNotSupportedException
Returns a clone if the implementation is cloneable.
Overrides:
clone in class Object
Returns:
a clone if the implementation is cloneable.
Throws:
CloneNotSupportedException - if this is called on an implementation that does not support Cloneable.
See Also:

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/17/docs/api/java.base/javax/crypto/MacSpi.html