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
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionclone()
Returns a clone if the implementation is cloneable.protected abstract byte[]
Completes the MAC computation and resets the MAC for further use, maintaining the secret key that the MAC was initialized with.protected abstract int
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
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 firstlen
bytes ininput
, starting atoffset
inclusive.protected void
engineUpdate(ByteBuffer input)
Processesinput.remaining()
bytes in the ByteBufferinput
, starting atinput.position()
.
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Constructor Details
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MacSpi
public MacSpi()Constructor for subclasses to call.
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Method Details
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engineGetMacLength
protected abstract int engineGetMacLength()Returns the length of the MAC in bytes.- Returns:
- the MAC length in bytes.
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engineInit
protected abstract void engineInit(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterExceptionInitializes 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.
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engineUpdate
protected abstract void engineUpdate(byte input)Processes the given byte.- Parameters:
input
- the input byte to be processed.
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engineUpdate
protected abstract void engineUpdate(byte[] input, int offset, int len)Processes the firstlen
bytes ininput
, starting atoffset
inclusive.- Parameters:
input
- the input buffer.offset
- the offset ininput
where the input starts.len
- the number of bytes to process.
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engineUpdate
Processesinput.remaining()
bytes in the ByteBufferinput
, starting atinput.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
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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.
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engineReset
protected abstract void engineReset()Resets the MAC for further use, maintaining the secret key that the MAC was initialized with. -
clone
Returns a clone if the implementation is cloneable.- Overrides:
clone
in classObject
- Returns:
- a clone if the implementation is cloneable.
- Throws:
CloneNotSupportedException
- if this is called on an implementation that does not supportCloneable
.- See Also:
Cloneable
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