javacard.security
Class RandomData

java.lang.Object
  javacard.security.RandomData

public abstract class RandomData

extends Object

The RandomData abstract class is the base class for random number generation. Implementations of RandomData algorithms must extend this class and implement all the abstract methods.

Field Summary

static byte	ALG_PSEUDO_RANDOM Utility pseudo-random number generation algorithms.
static byte	ALG_SECURE_RANDOM Cryptographically secure random number generation algorithms.

Constructor Summary

protected

RandomData() Protected constructor for subclassing.

Method Summary

abstract void	generateData(byte[] buffer, short offset, short length) Generates random data.
static RandomData	getInstance(byte algorithm) Creates a RandomData instance of the selected algorithm.
abstract void	setSeed(byte[] buffer, short offset, short length) Seeds the random data generator.

Methods inherited from class java.lang.Object

equals

Field Detail

ALG_PSEUDO_RANDOM

public static final byte ALG_PSEUDO_RANDOM

Utility pseudo-random number generation algorithms. The random number sequence generated by this algorithm need not be the same even if seeded with the same seed data.

Even if a transaction is in progress, the update of the internal state shall not participate in the transaction.

See Also:

Constant Field Values

ALG_SECURE_RANDOM

public static final byte ALG_SECURE_RANDOM

Cryptographically secure random number generation algorithms.

See Also:

Constant Field Values

Constructor Detail

RandomData

protected RandomData()

Protected constructor for subclassing.

Method Detail

getInstance

public static final RandomData getInstance(byte algorithm)
                                    throws CryptoException

Creates a RandomData instance of the selected algorithm. The pseudo random RandomData instance's seed is initialized to a internal default value.

Parameters:

algorithm - the desired random number algorithm. Valid codes listed in ALG_ .. constants above. See ALG_PSEUDO_RANDOM.

Returns:

the RandomData object instance of the requested algorithm

Throws:

CryptoException - with the following reason codes:

• CryptoException.NO_SUCH_ALGORITHM if the requested algorithm is not supported.

setSeed

public abstract void setSeed(byte[] buffer,
                             short offset,
                             short length)

Seeds the random data generator.

Parameters:

buffer - the input buffer

offset - the offset into the input buffer

length - the length of the seed data

generateData

public abstract void generateData(byte[] buffer,
                                  short offset,
                                  short length)
                           throws CryptoException

Generates random data.

Parameters:

buffer - the output buffer

offset - the offset into the output buffer

length - the length of random data to generate

Throws:

CryptoException - with the following reason codes:

• CryptoException.ILLEGAL_VALUE if the length parameter is zero.