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.- Since:
- 1.4
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionprotected abstract byte[]
Generates the exemption mechanism key blob.protected abstract int
engineGenExemptionBlob
(byte[] output, int outputOffset) Generates the exemption mechanism key blob, and stores the result in theoutput
buffer, starting atoutputOffset
inclusive.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 nextengineGenExemptionBlob
operation, given the input lengthinputLen
(in bytes).protected abstract void
engineInit
(Key key) Initializes this exemption mechanism with a key.protected abstract void
engineInit
(Key key, AlgorithmParameters params) Initializes this exemption mechanism with a key and a set of algorithm parameters.protected abstract void
engineInit
(Key key, AlgorithmParameterSpec params) Initializes this exemption mechanism with a key and a set of algorithm parameters.
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Constructor Details
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ExemptionMechanismSpi
public ExemptionMechanismSpi()Constructor for subclasses to call.
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Method Details
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engineGetOutputSize
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 nextengineGenExemptionBlob
operation, given the input lengthinputLen
(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)
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engineInit
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, anInvalidKeyException
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.
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engineInit
protected abstract void engineInit(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException, ExemptionMechanismException 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, anInvalidAlgorithmParameterException
is raised.- Parameters:
key
- the key for this exemption mechanismparams
- 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.
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engineInit
protected abstract void engineInit(Key key, AlgorithmParameters params) throws InvalidKeyException, InvalidAlgorithmParameterException, ExemptionMechanismException 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, anInvalidAlgorithmParameterException
is raised.- Parameters:
key
- the key for this exemption mechanismparams
- 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.
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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.
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engineGenExemptionBlob
protected abstract int engineGenExemptionBlob(byte[] output, int outputOffset) throws ShortBufferException, ExemptionMechanismException Generates the exemption mechanism key blob, and stores the result in theoutput
buffer, starting atoutputOffset
inclusive.If the
output
buffer is too small to hold the result, aShortBufferException
is thrown. In this case, repeat this call with a larger output buffer. UseengineGetOutputSize
to determine how big the output buffer should be.- Parameters:
output
- the buffer for the resultoutputOffset
- the offset inoutput
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.
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