ExemptionMechanismSpi

public abstract class ExemptionMechanismSpi extends Object

This class defines the Service Provider Interface (SPI) for the ExemptionMechanism 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 exemption mechanism.

Public Constructor Summary

Protected Method Summary

abstract byte[]
engineGenExemptionBlob()
Generates the exemption mechanism key blob.
abstract int
engineGenExemptionBlob(byte[] output, int outputOffset)
Generates the exemption mechanism key blob, and stores the result in the output buffer, starting at outputOffset inclusive.
abstract int
engineGetOutputSize(int inputLen)
Returns the length in bytes that an output buffer would need to be in order to hold the result of the next engineGenExemptionBlob operation, given the input length inputLen (in bytes).
abstract void
engineInit(Key key)
Initializes this exemption mechanism with a key.
abstract void
engineInit(Key key, AlgorithmParameterSpec params)
Initializes this exemption mechanism with a key and a set of algorithm parameters.
abstract void
engineInit(Key key, AlgorithmParameters params)
Initializes this exemption mechanism with a key and a set of algorithm parameters.

Inherited Method Summary

Public Constructors

public ExemptionMechanismSpi ()

Protected Methods

protected abstract byte[] engineGenExemptionBlob ()

Generates the exemption mechanism key blob.

Returns
  • the new buffer with the result key blob.
Throws
ExemptionMechanismException if problem(s) encountered in the process of generating.

protected abstract int engineGenExemptionBlob (byte[] output, int outputOffset)

Generates the exemption mechanism key blob, and stores the result in the output buffer, starting at outputOffset inclusive.

If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use engineGetOutputSize to determine how big the output buffer should be.

Parameters
output the buffer for the result
outputOffset the offset in output where the result is stored
Returns
  • the number of bytes stored in output
Throws
ShortBufferException if the given output buffer is too small to hold the result.
ExemptionMechanismException if problem(s) encountered in the process of generating.

protected abstract int engineGetOutputSize (int inputLen)

Returns the length in bytes that an output buffer would need to be in order to hold the result of the next engineGenExemptionBlob operation, given the input length inputLen (in bytes).

The actual output length of the next engineGenExemptionBlob call may be smaller than the length returned by this method.

Parameters
inputLen the input length (in bytes)
Returns
  • the required output buffer size (in bytes)

protected abstract void engineInit (Key key)

Initializes this exemption mechanism with a key.

If this exemption mechanism requires any algorithm parameters that cannot be derived from the given key, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, an InvalidKeyException is raised.

Parameters
key the key for this exemption mechanism
Throws
InvalidKeyException if the given key is inappropriate for this exemption mechanism.
ExemptionMechanismException if problem(s) encountered in the process of initializing.

protected abstract void engineInit (Key key, AlgorithmParameterSpec params)

Initializes this exemption mechanism with a key and a set of algorithm parameters.

If this exemption mechanism requires any algorithm parameters and params is null, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, an InvalidAlgorithmParameterException is raised.

Parameters
key the key for this exemption mechanism
params the algorithm parameters
Throws
InvalidKeyException if the given key is inappropriate for this exemption mechanism.
InvalidAlgorithmParameterException if the given algorithm parameters are inappropriate for this exemption mechanism.
ExemptionMechanismException if problem(s) encountered in the process of initializing.

protected abstract void engineInit (Key key, AlgorithmParameters params)

Initializes this exemption mechanism with a key and a set of algorithm parameters.

If this exemption mechanism requires any algorithm parameters and params is null, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, an InvalidAlgorithmParameterException is raised.

Parameters
key the key for this exemption mechanism
params the algorithm parameters
Throws
InvalidKeyException if the given key is inappropriate for this exemption mechanism.
InvalidAlgorithmParameterException if the given algorithm parameters are inappropriate for this exemption mechanism.
ExemptionMechanismException if problem(s) encountered in the process of initializing.