iaik.pkcs.pkcs11.provider.random

Class PKCS11SeededRandomSpi

java.lang.Object

java.security.SecureRandomSpi

iaik.pkcs.pkcs11.provider.random.PKCS11RandomSpi

iaik.pkcs.pkcs11.provider.random.PKCS11SeededRandomSpi

All Implemented Interfaces:

PKCS11EngineClass, java.io.Serializable

public class PKCS11SeededRandomSpi
extends PKCS11RandomSpi

An implementation of the SecureRandomSpi that uses a PKCS#11 token to gereate seed bytes. For random data it uses a software implementation. If this object is created using the default constructor, and this is always the case when instantiated through the JCA mechanism, this implementation always links to the first instance of IAIKPkcs11. The only way to link to a different instance is to instantiate the PKCS11Random class directly and to specify the provider. This implementation gets random data from a software implementation and gets seed bytes directly from the token. It does not send any seed bytes to the token. Moreover, it automatically gets 1024 bits of seed from the token upon the first request for random data. If more seed data is required, the application can get more seed data from this object and subsequently set it to this engine object. If there is no token present at creation time of this object, or if the present token does not support random number generation, this implementation uses a software delegate to process all requests. Per default, the SHA1PRNG algorithm is used for the software delegate.

Author:

Karl Scheibelhofer

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	INITIAL_SEED_BYTES The number of initial seed bytes to get from the token to seed this object.
protected boolean	isSeeded_ If this object was already seeded with seed bytes from the token.

Fields inherited from class iaik.pkcs.pkcs11.provider.random.PKCS11RandomSpi

pkcs11OperationInitialized_, session_, SOFTWARE_SECURE_RANDOM_ALGORITHM, softwareDelegate_, tokenManager_, useSoftwareDelegation_

Constructor Summary

Constructors

Constructor and Description
PKCS11SeededRandomSpi() This default constructor always links this random class to the first provider instance, because there are no means in the JCE to find out our provider instance.
PKCS11SeededRandomSpi(TokenManager tokenManager) This constructor links this random class to the given token manager.

Method Summary

Modifier and Type	Method and Description
protected void	engineNextBytes(byte[] arrayToFill) Generates a user-specified number of random bytes from the software delegate.
protected void	engineSetSeed(byte[] seedBytes) Reseeds the software delegate of this object.
protected int	getInitialSeedByteNumber() Get the number of seed bytes to use for initial seeding of this random object.
protected void	initializeSeed() Initialize the seed of this secure random object.

Methods inherited from class iaik.pkcs.pkcs11.provider.random.PKCS11RandomSpi

engineGenerateSeed, finalize, finalizePkcs11Operation, getSoftwareDelegateAlgorithm, initialize, initializePkcs11Operation, initializeSession, initializeSoftwareDelegate, isSupportedBy

Methods inherited from class java.lang.Object

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

Field Detail

INITIAL_SEED_BYTES

protected static final int INITIAL_SEED_BYTES

The number of initial seed bytes to get from the token to seed this object.

See Also:

Constant Field Values

isSeeded_

protected boolean isSeeded_

If this object was already seeded with seed bytes from the token.

Constructor Detail

PKCS11SeededRandomSpi

public PKCS11SeededRandomSpi()
                      throws IAIKPkcs11Exception

This default constructor always links this random class to the first provider instance, because there are no means in the JCE to find out our provider instance.

Throws:

IAIKPkcs11Exception - If there is no IAIKPkcs11 instance available.

PKCS11SeededRandomSpi

public PKCS11SeededRandomSpi(TokenManager tokenManager)
                      throws IAIKPkcs11Exception

This constructor links this random class to the given token manager. It uses this token manager to access the token.

Parameters:

tokenManager - The manager of the token we use for random generation.

Throws:

IAIKPkcs11Exception - If there is no IAIKPkcs11 instance available.

Method Detail

getInitialSeedByteNumber

protected int getInitialSeedByteNumber()

Get the number of seed bytes to use for initial seeding of this random object.

Returns:

The number of seed bytes to use.

initializeSeed

protected void initializeSeed()

Initialize the seed of this secure random object. If possible, it gets the random seed from the token; otherwise it gets the seed from the software delegate. The number of seed bytes used is determined by the value returned by getInitialSeedByteNumber().

engineNextBytes

protected void engineNextBytes(byte[] arrayToFill)
                        throws IAIKPkcs11Exception

Generates a user-specified number of random bytes from the software delegate.

Overrides:

engineNextBytes in class PKCS11RandomSpi

Parameters:

arrayToFill - the array to be filled in with random bytes.

Throws:

IAIKPkcs11Exception - If generating random bytes fails.

Preconditions:

(arrayToFill <> null)

engineSetSeed

protected void engineSetSeed(byte[] seedBytes)
                      throws IAIKPkcs11Exception

Reseeds the software delegate of this object. It does not write any seed to the token.

Overrides:

engineSetSeed in class PKCS11RandomSpi

Parameters:

seedBytes - The seed bytes.

Throws:

IAIKPkcs11Exception - If seeding the random fails.

Preconditions:

(seedBytes <> null)