public class

SecretKeyFactory

extends Object
java.lang.Object
   ↳ javax.crypto.SecretKeyFactory

Class Overview

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.

Application developers should refer to their provider's documentation to find out which key specifications are supported by the generateSecret and getKeySpec methods. For example, the DES secret-key factory supplied by the "SunJCE" provider supports DESKeySpec as a transparent representation of DES keys, and that provider's secret-key factory for Triple DES keys supports DESedeKeySpec as a transparent representation of Triple DES keys.

See Also

Summary

Protected Constructors
SecretKeyFactory(SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm)
Creates a SecretKeyFactory object.
Public Methods
final SecretKey generateSecret(KeySpec keySpec)
Generates a SecretKey object from the provided key specification (key material).
final String getAlgorithm()
Returns the algorithm name of this SecretKeyFactory object.
final static SecretKeyFactory getInstance(String algorithm, String provider)
Returns a SecretKeyFactory object that converts secret keys of the specified algorithm.
final static SecretKeyFactory getInstance(String algorithm, Provider provider)
Returns a SecretKeyFactory object that converts secret keys of the specified algorithm.
final static SecretKeyFactory getInstance(String algorithm)
Returns a SecretKeyFactory object that converts secret keys of the specified algorithm.
final KeySpec getKeySpec(SecretKey key, Class keySpec)
Returns a specification (key material) of the given key object in the requested format.
final Provider getProvider()
Returns the provider of this SecretKeyFactory object.
final SecretKey translateKey(SecretKey key)
Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this secret-key factory.
[Expand]
Inherited Methods
From class java.lang.Object

Protected Constructors

protected SecretKeyFactory (SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm)

Creates a SecretKeyFactory object.

Parameters
keyFacSpi the delegate
provider the provider
algorithm the secret-key algorithm

Public Methods

public final SecretKey generateSecret (KeySpec keySpec)

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.

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.

public static final SecretKeyFactory getInstance (String algorithm, String provider)

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

A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

Parameters
algorithm the standard name of the requested secret-key algorithm. See Appendix A in the Java Cryptography Architecture Reference Guide for information about standard algorithm names.
provider the name of the provider.
Returns
  • the new SecretKeyFactory object.
Throws
NoSuchAlgorithmException if a SecretKeyFactorySpi implementation for the specified algorithm is not available from the specified provider.
NullPointerException if the specified algorithm is null.
NoSuchProviderException if the specified provider is not registered in the security provider list.
IllegalArgumentException if the provider is null or empty.
See Also

public static final SecretKeyFactory getInstance (String algorithm, Provider provider)

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

A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.

Parameters
algorithm the standard name of the requested secret-key algorithm. See Appendix A in the Java Cryptography Architecture Reference Guide for information about standard algorithm names.
provider the provider.
Returns
  • the new SecretKeyFactory object.
Throws
NullPointerException if the specified algorithm is null.
NoSuchAlgorithmException if a SecretKeyFactorySpi implementation for the specified algorithm is not available from the specified Provider object.
IllegalArgumentException if the provider is null.
See Also

public static final SecretKeyFactory getInstance (String algorithm)

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.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

Parameters
algorithm the standard name of the requested secret-key algorithm. See Appendix A in the Java Cryptography Architecture Reference Guide for information about standard algorithm names.
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.
See Also

public final KeySpec getKeySpec (SecretKey key, Class keySpec)

Returns a specification (key material) of the given key object in the requested format.

Parameters
key the key
keySpec the requested format in which the key material shall be returned
Returns
  • the underlying key specification (key material) in the requested format
Throws
InvalidKeySpecException if the requested key specification is inappropriate for the given key (e.g., the algorithms associated with key and keySpec do not match, or key references a key on a cryptographic hardware device whereas keySpec is the specification of a software-based key), or the given key cannot be dealt with (e.g., the given key has an algorithm or format not supported by this secret-key factory).

public final Provider getProvider ()

Returns the provider of this SecretKeyFactory object.

Returns
  • the provider of this SecretKeyFactory object

public final SecretKey translateKey (SecretKey key)

Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this secret-key factory.

Parameters
key the key whose provider is unknown or untrusted
Returns
  • the translated key
Throws
InvalidKeyException if the given key cannot be processed by this secret-key factory.