Class SecretKeyFactory
 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 bidirectional, 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 DESede (Triple DES) secret-key factory supplied by the
 "SunJCE" provider supports DESedeKeySpec as a transparent
 representation of Triple DES keys.
 
 Every implementation of the Java platform is required to support the
 following standard SecretKeyFactory algorithms:
 
- DESede
- Since:
- 1.4
- See Also:
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Constructor SummaryConstructorsModifierConstructorDescriptionprotectedSecretKeyFactory(SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm) Creates aSecretKeyFactoryobject.
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Method SummaryModifier and TypeMethodDescriptionfinal SecretKeygenerateSecret(KeySpec keySpec) Generates aSecretKeyobject from the provided key specification (key material).final StringReturns the algorithm name of thisSecretKeyFactoryobject.static final SecretKeyFactorygetInstance(String algorithm) Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.static final SecretKeyFactorygetInstance(String algorithm, String provider) Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.static final SecretKeyFactorygetInstance(String algorithm, Provider provider) Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.final KeySpecgetKeySpec(SecretKey key, Class<?> keySpec) Returns a specification (key material) of the given key object in the requested format.final ProviderReturns the provider of thisSecretKeyFactoryobject.final SecretKeytranslateKey(SecretKey key) Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this secret-key factory.
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Constructor Details- 
SecretKeyFactoryCreates aSecretKeyFactoryobject.- Parameters:
- keyFacSpi- the delegate
- provider- the provider
- algorithm- the secret-key algorithm
 
 
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Method Details- 
getInstanceReturns aSecretKeyFactoryobject 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 SecretKeyFactoryobject encapsulating theSecretKeyFactorySpiimplementation 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.- Implementation Note:
- The JDK Reference Implementation additionally uses the
 jdk.security.provider.preferredSecurityproperty to determine the preferred provider order for the specified algorithm. This may be different from the order of providers returned bySecurity.getProviders().
- Parameters:
- algorithm- the standard name of the requested secret-key algorithm. See the SecretKeyFactory section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
- Returns:
- the new SecretKeyFactoryobject
- Throws:
- NoSuchAlgorithmException- if no- Providersupports a- SecretKeyFactorySpiimplementation for the specified algorithm
- NullPointerException- if- algorithmis- null
- See Also:
 
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getInstancepublic static final SecretKeyFactory getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.A new SecretKeyFactoryobject encapsulating theSecretKeyFactorySpiimplementation 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 the SecretKeyFactory section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
- provider- the name of the provider.
- Returns:
- the new SecretKeyFactoryobject
- Throws:
- IllegalArgumentException- if the- provideris- nullor empty
- NoSuchAlgorithmException- if a- SecretKeyFactorySpiimplementation for the specified algorithm is not available from the specified provider
- NoSuchProviderException- if the specified provider is not registered in the security provider list
- NullPointerException- if- algorithmis- null
- See Also:
 
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getInstancepublic static final SecretKeyFactory getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.A new SecretKeyFactoryobject encapsulating theSecretKeyFactorySpiimplementation 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 the SecretKeyFactory section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
- provider- the provider.
- Returns:
- the new SecretKeyFactoryobject
- Throws:
- IllegalArgumentException- if the- provideris- null
- NoSuchAlgorithmException- if a- SecretKeyFactorySpiimplementation for the specified algorithm is not available from the specified- Providerobject
- NullPointerException- if- algorithmis- null
- See Also:
 
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getProviderReturns the provider of thisSecretKeyFactoryobject.- Returns:
- the provider of this SecretKeyFactoryobject
 
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getAlgorithmReturns the algorithm name of thisSecretKeyFactoryobject.This is the same name that was specified in one of the getInstancecalls that created thisSecretKeyFactoryobject.- Returns:
- the algorithm name of this SecretKeyFactoryobject.
 
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generateSecretGenerates aSecretKeyobject 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.
 
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getKeySpecReturns 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- keyand- keySpecdo not match, or- keyreferences a key on a cryptographic hardware device whereas- keySpecis 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).
 
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translateKeyTranslates 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.
 
 
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