- java.lang.Object
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- javax.crypto.SecretKeyFactory
 
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 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 generateSecretandgetKeySpecmethods. For example, the DES secret-key factory supplied by the "SunJCE" provider supportsDESKeySpecas a transparent representation of DES keys, and that provider's secret-key factory for Triple DES keys supportsDESedeKeySpecas a transparent representation of Triple DES keys.Every implementation of the Java platform is required to support the following standard SecretKeyFactoryalgorithms:- DES
- DESede
 - Since:
- 1.4
- See Also:
- SecretKey,- DESKeySpec,- DESedeKeySpec,- PBEKeySpec
 
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Constructor SummaryConstructors Modifier Constructor Description protectedSecretKeyFactory(SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm)Creates a SecretKeyFactory object.
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Method SummaryAll Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description SecretKeygenerateSecret(KeySpec keySpec)Generates aSecretKeyobject from the provided key specification (key material).StringgetAlgorithm()Returns the algorithm name of thisSecretKeyFactoryobject.static SecretKeyFactorygetInstance(String algorithm)Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.static SecretKeyFactorygetInstance(String algorithm, String provider)Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.static SecretKeyFactorygetInstance(String algorithm, Provider provider)Returns aSecretKeyFactoryobject that converts secret keys of the specified algorithm.KeySpecgetKeySpec(SecretKey key, Class<?> keySpec)Returns a specification (key material) of the given key object in the requested format.ProvidergetProvider()Returns the provider of thisSecretKeyFactoryobject.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 Detail- 
SecretKeyFactoryprotected SecretKeyFactory(SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm) Creates a SecretKeyFactory object.- Parameters:
- keyFacSpi- the delegate
- provider- the provider
- algorithm- the secret-key algorithm
 
 
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Method Detail- 
getInstancepublic static final SecretKeyFactory getInstance(String algorithm) throws NoSuchAlgorithmException Returns 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 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.- 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 than 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:
- Provider
 
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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 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 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:
- Provider
 
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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 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 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:
- Provider
 
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getProviderpublic final Provider getProvider() Returns the provider of thisSecretKeyFactoryobject.- Returns:
- the provider of this SecretKeyFactoryobject
 
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getAlgorithmpublic final String getAlgorithm() Returns 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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generateSecretpublic final SecretKey generateSecret(KeySpec keySpec) throws InvalidKeySpecException Generates 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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getKeySpecpublic 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:
- 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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translateKeypublic 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 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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