# Enum Class DrbgParameters.Capability

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

All Implemented Interfaces:
  `Serializable`, `Comparable<DrbgParameters.Capability>`, `Constable`

Enclosing class:
  `DrbgParameters`

public static enum DrbgParameters.Capability extends Enum<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
--- | ---
NONE | NONE, RESEED_ONLY, PR_AND_RESEED
RESEED_ONLY | RESEED_ONLY, PR_AND_RESEED
PR_AND_RESEED | PR_AND_RESEED

A DRBG implementation supporting prediction resistance must also support reseeding.

Since:
  9

- ## Nested Class Summary

  ### Nested classes/interfaces declared in class java.lang.Enum

  `Enum.EnumDesc<E extends Enum<E>>`

- ## Enum Constant Summary

  Enum Constants
  Enum Constant
  Description
  `NONE`
  Neither prediction resistance nor reseed.
  `PR_AND_RESEED`
  Both prediction resistance and reseed.
  `RESEED_ONLY`
  Reseed but no prediction resistance.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `boolean`
  `supportsPredictionResistance()`
  Returns whether this capability supports prediction resistance.
  `boolean`
  `supportsReseeding()`
  Returns whether this capability supports reseeding.
  `static DrbgParameters.Capability`
  `valueOf(String name)`
  Returns the enum constant of this class with the specified name.
  `static DrbgParameters.Capability[]`
  `values()`
  Returns an array containing the constants of this enum class, in the order they are declared.

  ### Methods declared in class java.lang.Enum

  `clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf`

  ### Methods declared in class java.lang.Object

  `getClass, notify, notifyAll, wait, wait, wait`

- ## Enum Constant Details

  - ### PR_AND_RESEED

    public static final DrbgParameters.Capability PR_AND_RESEED
    Both prediction resistance and reseed.

  - ### RESEED_ONLY

    public static final DrbgParameters.Capability RESEED_ONLY
    Reseed but no prediction resistance.

  - ### NONE

    public static final DrbgParameters.Capability NONE
    Neither prediction resistance nor reseed.

- ## Method Details

  - ### values

    public static DrbgParameters.Capability[] values()
    Returns an array containing the constants of this enum class, in the order they are declared.
    Returns:
      an array containing the constants of this enum class, in the order they are declared

  - ### valueOf

    public static DrbgParameters.Capability valueOf(String name)
    Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
    Parameters:
      `name` - the name of the enum constant to be returned.
    Returns:
      the enum constant with the specified name
    Throws:
      `IllegalArgumentException` - if this enum class has no constant with the specified name
      `NullPointerException` - if the argument is null

  - ### supportsReseeding

    public boolean supportsReseeding()
    Returns whether this capability supports reseeding.
    Returns:
      `true` for `PR_AND_RESEED` and `RESEED_ONLY`, and `false` for `NONE`

  - ### supportsPredictionResistance

    public boolean supportsPredictionResistance()
    Returns whether this capability supports prediction resistance.
    Returns:
      `true` for `PR_AND_RESEED`, and `false` for `RESEED_ONLY` and `NONE`