Class KEM.Encapsulator

java.lang.Object
javax.crypto.KEM.Encapsulator
Enclosing class:
KEM
public static final class KEM.Encapsulator extends Object
An encapsulator, generated by KEM.newEncapsulator(PublicKey) on the KEM sender side.

This class represents the key encapsulation function of a KEM. Each invocation of the encapsulate method generates a new secret key and key encapsulation message that is returned in an KEM.Encapsulated object.

Since:
21

  • Method Summary

    Modifier and Type
    Method
    Description
    KEM.Encapsulated
    encapsulate()
    The key encapsulation function.
    KEM.Encapsulated
    encapsulate(int from, int to, String algorithm)
    The key encapsulation function.
    int
    encapsulationSize()
    Returns the size of the key encapsulation message.
    String
    providerName()
    Returns the name of the provider.
    int
    secretSize()
    Returns the size of the shared secret.

    Methods declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Creates and returns a copy of this object.
    boolean
    equals(Object obj)
    Indicates whether some other object is "equal to" this one.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Finalization is deprecated and subject to removal in a future release.
    final Class<?>
    getClass()
    Returns the runtime class of this Object.
    int
    hashCode()
    Returns a hash code value for this object.
    final void
    notify()
    Wakes up a single thread that is waiting on this object's monitor.
    final void
    notifyAll()
    Wakes up all threads that are waiting on this object's monitor.
    String
    toString()
    Returns a string representation of the object.
    final void
    wait()
    Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
    final void
    wait(long timeoutMillis)
    Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
    final void
    wait(long timeoutMillis, int nanos)
    Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

  • Method Details

    • providerName

      public String providerName()
      Returns the name of the provider.
      Returns:
      the name of the provider

    • encapsulate

      public KEM.Encapsulated encapsulate()
      The key encapsulation function.

      This method is equivalent to encapsulate(0, secretSize(), "Generic"). This combination of arguments must be supported by every implementation.

      The generated secret key is usually passed to a key derivation function (KDF) as the input keying material.

      Returns:
      a KEM.Encapsulated object containing the shared secret, key encapsulation message, and optional parameters. The shared secret is a SecretKey containing all of the bytes of the secret, and an algorithm name of "Generic".

    • encapsulate

      public KEM.Encapsulated encapsulate(int from, int to, String algorithm)
      The key encapsulation function.

      Each invocation of this method generates a new secret key and key encapsulation message that is returned in an KEM.Encapsulated object.

      An implementation may choose to not support arbitrary combinations of from, to, and algorithm.

      Parameters:
      from - the initial index of the shared secret byte array to be returned, inclusive
      to - the final index of the shared secret byte array to be returned, exclusive
      algorithm - the algorithm name for the secret key that is returned. See the SecretKey Algorithms section in the Java Security Standard Algorithm Names Specification for information about standard secret key algorithm names. Specify "Generic" if the output will be used as the input keying material of a key derivation function (KDF).
      Returns:
      a KEM.Encapsulated object containing a portion of the shared secret, key encapsulation message, and optional parameters. The portion of the shared secret is a SecretKey containing the bytes of the secret ranging from from to to, exclusive, and an algorithm name as specified. For example, encapsulate(0, 16, "AES") uses the first 16 bytes of the shared secret as a 128-bit AES key.
      Throws:
      IndexOutOfBoundsException - if from < 0, from > to, or to > secretSize()
      NullPointerException - if algorithm is null
      UnsupportedOperationException - if the combination of from, to, and algorithm is not supported by the encapsulator
      External Specifications

    • secretSize

      public int secretSize()
      Returns the size of the shared secret.

      This method can be called to find out the length of the shared secret before encapsulate is called or if the obtained SecretKey is not extractable.

      Returns:
      the size of the shared secret

    • encapsulationSize

      public int encapsulationSize()
      Returns the size of the key encapsulation message.

      This method can be called to find out the length of the encapsulation message before encapsulate is called.

      Returns:
      the size of the key encapsulation message