ExemptionMechanismSpi

public abstract class ExemptionMechanismSpi
extends Object

java.lang.Object
   ↳ javax.crypto.ExemptionMechanismSpi


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.

Summary

Public constructors

ExemptionMechanismSpi()

Protected methods

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 methods

Public constructors

ExemptionMechanismSpi

added in API level 1
public ExemptionMechanismSpi ()

Protected methods

engineGenExemptionBlob

added in API level 1
protected abstract byte[] engineGenExemptionBlob ()

Generates the exemption mechanism key blob.

Returns
byte[] the new buffer with the result key blob.

Throws
ExemptionMechanismException if problem(s) encountered in the process of generating.

engineGenExemptionBlob

added in API level 1
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 byte: the buffer for the result

outputOffset int: the offset in output where the result is stored

Returns
int 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.

engineGetOutputSize

added in API level 1
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 int: the input length (in bytes)

Returns
int the required output buffer size (in bytes)

engineInit

added in API level 1
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 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.

engineInit

added in API level 1
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 Key: the key for this exemption mechanism

params AlgorithmParameterSpec: 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.

engineInit

added in API level 1
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 Key: the key for this exemption mechanism

params AlgorithmParameters: 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.