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Class javax.crypto.SecretKeyFactory

java.lang.Object
    |
    +----javax.crypto.SecretKeyFactory

public class SecretKeyFactory
extends java.lang.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 SecretKeyFactory for DES of the Sun provider supports DESKeySpec, and the SecretKeyFactory for Triple DES of the same provider supports DESedeKeySpec.

See Also:
SecretKey, java.security.Key, java.security.KeyFactory, java.security.spec.KeySpec, DESKeySpec, DESedeKeySpec, PBEKeySpec

Constructor Summary
 SecretKeyFactory(SecretKeyFactorySpi keyFacSpi, java.security.Provider provider, java.lang.String algorithm)
Creates a SecretKeyFactory object.
 

Method Summary
SecretKey  generateSecret(java.security.spec.KeySpec keySpec)
Generates a SecretKey object from the provided key specification (key material).
java.lang.String  getAlgorithm()
Returns the name of the algorithm associated with this key factory.
static SecretKeyFactory  getInstance(java.lang.String algorithm)
Generates a SecretKeyFactory object for the specified secret key algorithm.
static SecretKeyFactory  getInstance(java.lang.String algorithm, java.lang.String provider)
Generates a SecretKeyFactory object for the specified secret key algorithm from the specified provider.
java.security.spec.KeySpec  getKeySpec(SecretKey key, java.lang.Class keySpec)
Returns a specification (key material) of the given key object in the requested format.
java.security.Provider  getProvider()
Returns the provider of this SecretKeyFactory object.
SecretKey  translateKey(SecretKey key)
Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.
 
Methods inherited from class java.lang.Object
 clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SecretKeyFactory

protected SecretKeyFactory(SecretKeyFactorySpi keyFacSpi,
                           java.security.Provider provider,
                           java.lang.String algorithm)
Creates a SecretKeyFactory object.
Parameters:
keyFacSpi - the delegate
provider - the provider
Method Detail

getInstance

public static final SecretKeyFactory getInstance(java.lang.String algorithm) throws java.security.NoSuchAlgorithmException
Generates a SecretKeyFactory object for the specified secret key algorithm. If the default provider package provides an implementation of the requested factory, an instance of SecretKeyFactory containing that implementation is returned. If the requested 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:
java.security.NoSuchAlgorithmException - if the requested algorithm is not available in the default provider package or any of the other provider packages that were searched.

getInstance

public static final SecretKeyFactory getInstance(java.lang.String algorithm,
                                                 java.lang.String provider) throws java.security.NoSuchAlgorithmException, java.security.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:
java.security.NoSuchAlgorithmException - if the algorithm is not available from the specified provider.
java.security.NoSuchProviderException - if the provider has not been configured.
See Also:
java.security.Provider

getProvider

public final java.security.Provider getProvider()
Returns the provider of this SecretKeyFactory object.
Returns:
the provider of this SecretKeyFactory object

getAlgorithm

public final java.lang.String getAlgorithm()
Returns the name of the algorithm associated with this key factory.

generateSecret

public final SecretKey generateSecret(java.security.spec.KeySpec keySpec) throws java.security.spec.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:
java.security.spec.InvalidKeySpecException - if the given key specification is inappropriate for this key factory to produce a secret key.

getKeySpec

public final java.security.spec.KeySpec getKeySpec(SecretKey key,
                                java.lang.Class keySpec) throws java.security.spec.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:
the underlying key specification (key material) in the requested format
Throws:
java.security.spec.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 unrecognized algorithm or format).

translateKey

public final SecretKey translateKey(SecretKey key) throws java.security.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:
java.security.InvalidKeyException - if the given key cannot be processed by this key factory.

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