javax.crypto

Class SecretKeyFactory

java.lang.Object

javax.crypto.SecretKeyFactory

public class SecretKeyFactory
extends Object

This class represents a factory for secret keys.

Key factories are used to convert keys (opaque cryptographic keys of type Key) into key specifications (transparent representations of the underlying key material), and vice versa. Secret key factories operate only on secret (symmetric) keys.

Key factories are bi-directional, i.e., they allow to build an opaque key object from a given key specification (key material), or to retrieve the underlying key material of a key object in a suitable format.

Every implementation of the Java platform is required to support the following standard SecretKeyFactory algorithms:

• DES
• DESede

These algorithms are described in the Signature section of the Java Security Standard Algorithm Names Specification. Consult the release documentation for your implementation to see if any other algorithms are supported.

Since:

1.4

Author:

Jan Luehe

See Also:

SecretKey, PBEKeySpec

Method Summary

Modifier and Type	Method and Description
SecretKey	generateSecret(KeySpec keySpec) Generates a SecretKey object from the provided key specification (key material).
String	getAlgorithm() Returns the algorithm name of this SecretKeyFactory object.
static SecretKeyFactory	getInstance(String algorithm) Returns a SecretKeyFactory object that converts secret keys of the specified algorithm.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

generateSecret

public final SecretKey generateSecret(KeySpec keySpec)
                               throws InvalidKeySpecException

Generates a SecretKey object from the provided key specification (key material).

Parameters:

keySpec - the specification (key material) of the secret key

Returns:

the secret key

Throws:

InvalidKeySpecException - if the given key specification is inappropriate for this secret-key factory to produce a secret key.

getAlgorithm

public final String getAlgorithm()

Returns the algorithm name of this SecretKeyFactory object.

This is the same name that was specified in one of the getInstance calls that created this SecretKeyFactory object.

Returns:

the algorithm name of this SecretKeyFactory object.

getInstance

public static final SecretKeyFactory getInstance(String algorithm)
                                          throws NoSuchAlgorithmException

Returns a SecretKeyFactory object that converts secret keys of the specified algorithm.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the first Provider that supports the specified algorithm is returned.

Parameters:

algorithm - the standard name of the requested secret-key algorithm. See the SecretKeyFactory section in the Signature section of the Java Security Standard Algorithm Names Specification. Consult the release documentation for your implementation to see if any other algorithms are supported.

Returns:

the new SecretKeyFactory object.

Throws:

NullPointerException - if the specified algorithm is null.

NoSuchAlgorithmException - if no Provider supports a SecretKeyFactorySpi implementation for the specified algorithm.