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Class javax.crypto.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.

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:
SecretKey, DESKeySpec, DESedeKeySpec, PBEKeySpec

Constructor Index

 o SecretKeyFactory(SecretKeyFactorySpi, Provider, String)
Creates a SecretKeyFactory object.

Method Index

 o generateSecret(KeySpec)
Generates a SecretKey object from the provided key specification (key material).
 o getAlgorithm()
Returns the algorithm name of this SecretKeyFactory object.
 o getInstance(String)
Generates a SecretKeyFactory object for the specified secret key algorithm.
 o getInstance(String, String)
Generates a SecretKeyFactory object for the specified secret key algorithm from the specified provider.
 o getKeySpec(SecretKey, Class)
Returns a specification (key material) of the given key object in the requested format.
 o getProvider()
Returns the provider of this SecretKeyFactory object.
 o translateKey(SecretKey)
Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.

Constructors

 o SecretKeyFactory
 protected SecretKeyFactory(SecretKeyFactorySpi keyFacSpi,
                            Provider provider,
                            String algorithm)
Creates a SecretKeyFactory object.

Parameters:
keyFacSpi - the delegate
provider - the provider

Methods

 o getInstance
 public static final SecretKeyFactory getInstance(String algorithm) throws NoSuchAlgorithmException
Generates a SecretKeyFactory object for the specified secret key algorithm. If the default provider package contains a SecretKeyFactory subclass for the specified algorithm, an instance of that subclass is returned. If such a key factory is not available in the default provider package, other provider packages are searched.

Parameters:
algorithm - the standard name of the requested secret key algorithm. See Appendix A in the Java Cryptography Extension API Specification & Reference for information about standard algorithm names.
Returns:
a SecretKeyFactory object for the specified secret key algorithm.
Throws: NoSuchAlgorithmException
if the requested algorithm is not available in the default provider package or any of the other provider packages that were searched.
 o getInstance
 public static final SecretKeyFactory getInstance(String algorithm,
                                                  String provider) throws NoSuchAlgorithmException, NoSuchProviderException
Generates a SecretKeyFactory object for the specified secret key algorithm from the specified provider.

Parameters:
algorithm - the standard name of the requested secret key algorithm. See Appendix A in the Java Cryptography Extension API Specification & Reference for information about standard algorithm names.
provider - the name of the provider.
Returns:
a SecretKeyFactory object for the specified secret key algorithm.
Throws: NoSuchAlgorithmException
if the algorithm is not available from the specified provider.
Throws: NoSuchProviderException
if the provider has not been configured.
 o getProvider
 public final Provider getProvider()
Returns the provider of this SecretKeyFactory object.

Returns:
the provider of this SecretKeyFactory object
 o 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.
 o 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 key factory to produce a secret
 o getKeySpec
 public final KeySpec getKeySpec(SecretKey key,
                                 Class keySpec) throws InvalidKeySpecException
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:
s the underlying key specification (key material) in the requested format
Throws: InvalidKeySpecException
if the requested key specification is inappropriate for the given key, or the given key cannot be processed (e.g., the given key has an unrecognised algorithm or format).
 o translateKey
 public final SecretKey translateKey(SecretKey key) throws InvalidKeyException
Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this 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 key factory.

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