Module java.base

Package javax.crypto

Interface KEMSpi.DecapsulatorSpi

Enclosing interface:

KEMSpi

public static interface KEMSpi.DecapsulatorSpi

The KEM decapsulator implementation, generated by KEMSpi.engineNewDecapsulator(java.security.PrivateKey, java.security.spec.AlgorithmParameterSpec) on the KEM receiver side.

API Note:

This interface is defined in Java SE 17 Maintenance Release 1.

Since:

17

See Also:

• KEM.Decapsulator

Method Summary

Modifier and Type	Method	Description
SecretKey	engineDecapsulate(byte[] encapsulation, int from, int to, String algorithm)	The key decapsulation function.
int	engineEncapsulationSize()	Returns the size of the key encapsulation message.
int	engineSecretSize()	Returns the size of the shared secret.

Method Details

engineDecapsulate

SecretKey engineDecapsulate(byte[] encapsulation,
 int from,
 int to,
 String algorithm)
                     throws DecapsulateException

The key decapsulation function.

An invocation of this method recovers the secret key from the key encapsulation message.

An implementation must support the case where from is 0, to is the same as the return value of secretSize(), and algorithm is "Generic".

Parameters:

encapsulation - the key encapsulation message from the sender. The size must be equal to the value returned by engineEncapsulationSize() ()}, or a DecapsulateException must be thrown.

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

Returns:

a portion of the shared secret as a SecretKey with the specified algorithm

Throws:

DecapsulateException - if an error occurs during the decapsulation process

IndexOutOfBoundsException - if from < 0, from > to, or to > secretSize()

NullPointerException - if encapsulation or algorithm is null

UnsupportedOperationException - if the combination of from, to, and algorithm is not supported by the decapsulator

See Also:

• KEM.Decapsulator.decapsulate(byte[], int, int, String)

engineSecretSize

int engineSecretSize()

Returns the size of the shared secret.

Returns:

the size of the shared secret as a finite non-negative integer

See Also:

• KEM.Decapsulator.secretSize()

engineEncapsulationSize

int engineEncapsulationSize()

Returns the size of the key encapsulation message.

Returns:

the size of the key encapsulation message as a finite non-negative integer

See Also:

• KEM.Decapsulator.encapsulationSize()