iaik.pkcs.pkcs1
Class MaskGenerationAlgorithmSpi

java.lang.Object
  |
  +--iaik.pkcs.pkcs1.MaskGenerationAlgorithmSpi

Direct Known Subclasses:

MaskGenerationAlgorithm

public abstract class MaskGenerationAlgorithmSpi

extends Object

JCA compliant SPI class that provides the functionality of a PKCS#1v2.1 mask generation function.

Mask generation functions are used by the PKCS#1v2.1 PSS signature and OAEP encryption schemes:

 A mask generation function takes an octet string of variable length
 and a desired output length as input, and outputs an octet string of
 the desired length.  There may be restrictions on the length of the
 input and output octet strings, but such bounds are generally very
 large.  Mask generation functions are deterministic; the octet string
 output is completely determined by the input octet string.  The
 output of a mask generation function should be pseudorandom: Given
 one part of the output but not the input, it should be infeasible to
 predict another part of the output.  The provable security of RSAES-
 OAEP and RSASSA-PSS relies on the random nature of the output of the
 mask generation function, which in turn relies on the random nature
 of the underlying hash.
 

Version:

File Revision 8

See Also:

MaskGenerationAlgorithm

Constructor Summary

protected

MaskGenerationAlgorithmSpi() Default constructor.

Method Summary

Object	clone() Returns a clone if the implementation is cloneable.
protected abstract AlgorithmParameters	engineGetParameters() SPI: Gets the algorithm parameters required by this MGF engine.
protected abstract void	engineMask(byte[] mgfSeed, int mgfSeedOff, int mgfSeedLen, int maskLen, byte[] dst, int dstOff) SPI: Uses the mask generation function to generate maskLen bytes from the supplied seed mgfSeed[mgfSeedOff:mgfSeedLen] and XORs the result with dst[off:maskLen].
protected abstract void	engineReset() SPE: Resets this engine to the state before engineMask has been called.
protected abstract void	engineSetParameters(AlgorithmParameters params) SPI: Sets any algorithm parameters required by this MGF engine.
protected abstract void	engineSetParameters(AlgorithmParameterSpec paramSpec) SPI: Sets any algorithm parameters required by this MGF engine.

Methods inherited from class java.lang.Object

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

Constructor Detail

MaskGenerationAlgorithmSpi

protected MaskGenerationAlgorithmSpi()

Default constructor.

Method Detail

engineSetParameters

protected abstract void engineSetParameters(AlgorithmParameterSpec paramSpec)
                                     throws InvalidAlgorithmParameterException

SPI: Sets any algorithm parameters required by this MGF engine.

Parameters:

paramSpec - the parameters to be set

Throws:

InvalidAlgorithmParameterException - if the parameters are inappropriate for this engine or are invalid

engineSetParameters

protected abstract void engineSetParameters(AlgorithmParameters params)
                                     throws InvalidAlgorithmParameterException

SPI: Sets any algorithm parameters required by this MGF engine.

Parameters:

params - the parameters to be set

Throws:

InvalidAlgorithmParameterException - if the parameters are inappropriate for this engine or are invalid

engineGetParameters

protected abstract AlgorithmParameters engineGetParameters()

SPI: Gets the algorithm parameters required by this MGF engine.

Returns:

the parameters used by this engine

engineMask

protected abstract void engineMask(byte[] mgfSeed,
                                   int mgfSeedOff,
                                   int mgfSeedLen,
                                   int maskLen,
                                   byte[] dst,
                                   int dstOff)

SPI: Uses the mask generation function to generate maskLen bytes from the supplied seed mgfSeed[mgfSeedOff:mgfSeedLen] and XORs the result with dst[off:maskLen].

Parameters:

mgfSeed - the seed from which the mask is generated

mgfSeedOff - the offest indicating the start position within the seed array

mgfSeedLen - the actual number of seed bytes

maskLen - the number of required mask bytes

dst - the destination array to which to XOR the mask result

dstOff - the offset indicating the start position within the destination array

engineReset

protected abstract void engineReset()

SPE: Resets this engine to the state before engineMask has been called.

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.