SecureRandomSpi

public abstract class SecureRandomSpi
extends Object implements Serializable

java.lang.Object
   ↳ java.security.SecureRandomSpi


This class defines the Service Provider Interface (SPI) for the SecureRandom class.

All the abstract methods in this class must be implemented by each service provider who wishes to supply the implementation of a cryptographically strong pseudo-random number generator.

Summary

Public constructors

SecureRandomSpi()

Constructor without a parameter.

Protected constructors

SecureRandomSpi(SecureRandomParameters params)

Constructor with a parameter.

Public methods

String toString()

Returns a Human-readable string representation of this SecureRandom.

Protected methods

abstract byte[] engineGenerateSeed(int numBytes)

Returns the given number of seed bytes.

SecureRandomParameters engineGetParameters()

Returns the effective SecureRandomParameters for this SecureRandom instance.

void engineNextBytes(byte[] bytes, SecureRandomParameters params)

Generates a user-specified number of random bytes with additional parameters.

abstract void engineNextBytes(byte[] bytes)

Generates a user-specified number of random bytes.

void engineReseed(SecureRandomParameters params)

Reseeds this random object with entropy input read from its entropy source with additional parameters.

abstract void engineSetSeed(byte[] seed)

Reseeds this random object with the given seed.

Inherited methods

Public constructors

SecureRandomSpi

Added in API level 1
public SecureRandomSpi ()

Constructor without a parameter.

Protected constructors

SecureRandomSpi

Added in API level 1
protected SecureRandomSpi (SecureRandomParameters params)

Constructor with a parameter.

Parameters
params SecureRandomParameters: the SecureRandomParameters object. This argument can be null.

Throws
IllegalArgumentException if params is unrecognizable or unsupported by this SecureRandom

Public methods

toString

Added in API level 1
public String toString ()

Returns a Human-readable string representation of this SecureRandom.

Returns
String the string representation

Protected methods

engineGenerateSeed

Added in API level 1
protected abstract byte[] engineGenerateSeed (int numBytes)

Returns the given number of seed bytes. This call may be used to seed other random number generators.

Parameters
numBytes int: the number of seed bytes to generate.

Returns
byte[] the seed bytes.

engineGetParameters

protected SecureRandomParameters engineGetParameters ()

Returns the effective SecureRandomParameters for this SecureRandom instance.

Implementation Requirements:
  • The default implementation returns null.
Returns
SecureRandomParameters the effective SecureRandomParameters parameters, or null if no parameters were used.

engineNextBytes

protected void engineNextBytes (byte[] bytes, 
                SecureRandomParameters params)

Generates a user-specified number of random bytes with additional parameters.

Some random number generators can only generate a limited amount of random bytes per invocation. If the size of bytes is greater than this limit, the implementation should invoke its generation process multiple times to completely fill the buffer before returning from this method.

Implementation Requirements:
Parameters
bytes byte: the array to be filled in with random bytes

params SecureRandomParameters: additional parameters

Throws
UnsupportedOperationException if the implementation has not overridden this method
IllegalArgumentException if params is null, illegal or unsupported by this SecureRandom

engineNextBytes

Added in API level 1
protected abstract void engineNextBytes (byte[] bytes)

Generates a user-specified number of random bytes.

Some random number generators can only generate a limited amount of random bytes per invocation. If the size of bytes is greater than this limit, the implementation should invoke its generation process multiple times to completely fill the buffer before returning from this method.

Parameters
bytes byte: the array to be filled in with random bytes.

engineReseed

protected void engineReseed (SecureRandomParameters params)

Reseeds this random object with entropy input read from its entropy source with additional parameters.

If this method is called by SecureRandom#reseed(), params will be null.

Do not override this method if the implementation does not support reseeding.

Implementation Requirements:
Parameters
params SecureRandomParameters: extra parameters, can be null.

Throws
UnsupportedOperationException if the implementation has not overridden this method
IllegalArgumentException if params is illegal or unsupported by this SecureRandom

engineSetSeed

Added in API level 1
protected abstract void engineSetSeed (byte[] seed)

Reseeds this random object with the given seed. The seed supplements, rather than replaces, the existing seed. Thus, repeated calls are guaranteed never to reduce randomness.

Parameters
seed byte: the seed.