DrbgParameters.Capability

public static final enum DrbgParameters.Capability
extends Enum<DrbgParameters.Capability>

java.lang.Object
   ↳ java.lang.Enum<java.security.DrbgParameters.Capability>
     ↳ java.security.DrbgParameters.Capability


The reseedable and prediction resistance capabilities of a DRBG.

When this object is passed to a SecureRandom.getInstance() call, it is the requested minimum capability. When it's returned from SecureRandom.getParameters(), it is the effective capability.

Please note that while the Instantiate_function defined in NIST SP 800-90Ar1 only includes a prediction_resistance_flag parameter, the Capability type includes an extra value RESEED_ONLY because reseeding is an optional function. If NONE is used in an Instantiation object in calling the SecureRandom.getInstance method, the returned DRBG instance is not guaranteed to support reseeding. If RESEED_ONLY or PR_AND_RESEED is used, the instance must support reseeding.

The table below lists possible effective values if a certain capability is requested, i.e.

 Capability requested = ...;
 SecureRandom s = SecureRandom.getInstance("DRBG",
         DrbgParameters(-1, requested, null));
 Capability effective = ((DrbgParametes.Initiate) s.getParameters())
         .getCapability();
requested and effective capabilities
Requested Value Possible Effective Values
NONENONE, RESEED_ONLY, PR_AND_RESEED
RESEED_ONLYRESEED_ONLY, PR_AND_RESEED
PR_AND_RESEEDPR_AND_RESEED

A DRBG implementation supporting prediction resistance must also support reseeding.

Summary

Enum values

DrbgParameters.Capability  NONE

Neither prediction resistance nor reseed. 

DrbgParameters.Capability  PR_AND_RESEED

Both prediction resistance and reseed. 

DrbgParameters.Capability  RESEED_ONLY

Reseed but no prediction resistance. 

Public methods

boolean supportsPredictionResistance()

Returns whether this capability supports prediction resistance.

boolean supportsReseeding()

Returns whether this capability supports reseeding.

String toString()

Returns the name of this enum constant, as contained in the declaration.

static DrbgParameters.Capability valueOf(String name)
static final Capability[] values()

Inherited methods

Enum values

NONE

Added in API level 35
public static final DrbgParameters.Capability NONE

Neither prediction resistance nor reseed.

PR_AND_RESEED

Added in API level 35
public static final DrbgParameters.Capability PR_AND_RESEED

Both prediction resistance and reseed.

RESEED_ONLY

Added in API level 35
public static final DrbgParameters.Capability RESEED_ONLY

Reseed but no prediction resistance.

Public methods

supportsPredictionResistance

Added in API level 35
public boolean supportsPredictionResistance ()

Returns whether this capability supports prediction resistance.

Returns
boolean true for PR_AND_RESEED, and false for RESEED_ONLY and NONE

supportsReseeding

Added in API level 35
public boolean supportsReseeding ()

Returns whether this capability supports reseeding.

Returns
boolean true for PR_AND_RESEED and RESEED_ONLY, and false for NONE

toString

Added in API level 35
public String toString ()

Returns the name of this enum constant, as contained in the declaration. This method may be overridden, though it typically isn't necessary or desirable. An enum class should override this method when a more "programmer-friendly" string form exists.

Returns
String the name of this enum constant

valueOf

public static DrbgParameters.Capability valueOf (String name)

Parameters
name String

Returns
DrbgParameters.Capability

values

public static final Capability[] values ()

Returns
Capability[]