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java.lang.Objectjavax.crypto.SecretKeyFactory
public class SecretKeyFactory
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.
SecretKey
,
DESKeySpec
,
DESedeKeySpec
,
PBEKeySpec
Constructor Summary | |
---|---|
protected |
SecretKeyFactory(SecretKeyFactorySpi keyFacSpi,
Provider provider,
String algorithm)
Creates a SecretKeyFactory object. |
Method Summary | |
---|---|
SecretKey |
generateSecret(KeySpec keySpec)
Generates a SecretKey object from the provided key
specification (key material). |
String |
getAlgorithm()
Returns the algorithm name of this SecretKeyFactory
object. |
static SecretKeyFactory |
getInstance(String algorithm)
Generates a SecretKeyFactory object for the specified
secret-key algorithm. |
static SecretKeyFactory |
getInstance(String algorithm,
Provider provider)
Generates a SecretKeyFactory object for the specified
secret-key algorithm from the specified provider. |
static SecretKeyFactory |
getInstance(String algorithm,
String provider)
Generates a SecretKeyFactory object for the specified
secret-key algorithm from the specified provider. |
KeySpec |
getKeySpec(SecretKey key,
Class keySpec)
Returns a specification (key material) of the given key object in the requested format. |
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 secret-key factory. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll,
toString, wait, wait, wait |
Constructor Detail |
---|
protected SecretKeyFactory(SecretKeyFactorySpi keyFacSpi,
Provider provider,
String algorithm)
keyFacSpi
- the delegateprovider
- the provideralgorithm
- the secret-key
algorithmMethod Detail |
---|
public static final SecretKeyFactory getInstance(String algorithm)
throws NoSuchAlgorithmException
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.
algorithm
- the standard name
of the requested secret-key algorithm. See Appendix A in the
Java Cryptography Extension Reference Guide for information
about standard algorithm names.
SecretKeyFactory
object for
the specified secret-key algorithm.
NullPointerException
- if the specified algorithm is null.
NoSuchAlgorithmException
- if a secret-key factory for the specified algorithm is not available
in the default provider package or any of the other provider packages
that were searched.public static final SecretKeyFactory getInstance(String algorithm,
String provider)
throws NoSuchAlgorithmException,
NoSuchProviderException
SecretKeyFactory
object for the specified secret-key algorithm from the specified
provider.
algorithm
- the standard name
of the requested secret-key algorithm. See Appendix A in the
Java Cryptography Extension Reference Guide for information
about standard algorithm names.provider
- the name of the
provider.
SecretKeyFactory
object for
the specified secret-key algorithm.
NoSuchAlgorithmException
- if a secret-key factory for the specified algorithm is not available
from the specified provider.
NullPointerException
- if the specified algorithm is null.
NoSuchProviderException
- if the specified provider has not been configured.
IllegalArgumentException
- if the provider
is null.public static final SecretKeyFactory getInstance(String algorithm,
Provider provider)
throws NoSuchAlgorithmException
SecretKeyFactory
object for the specified secret-key algorithm from the specified
provider. Note: the provider
doesn't have to
be registered.
algorithm
- the standard name
of the requested secret-key algorithm. See Appendix A in the
Java Cryptography Extension Reference Guide for information
about standard algorithm names.provider
- the provider.
SecretKeyFactory
object for
the specified secret-key algorithm.
NullPointerException
- if the specified algorithm is null.
NoSuchAlgorithmException
- if a secret-key factory for the specified algorithm is not available
from the specified provider.
IllegalArgumentException
- if the provider
is null.public final Provider getProvider()
SecretKeyFactory
object.
SecretKeyFactory
objectpublic final String getAlgorithm()
SecretKeyFactory
object.
This is the same name that was specified in one of the getInstance
calls that created this SecretKeyFactory
object.
SecretKeyFactory
object.public final SecretKey generateSecret(KeySpec keySpec)
throws InvalidKeySpecException
SecretKey
object from
the provided key specification (key material).
keySpec
- the specification
(key material) of the secret key
InvalidKeySpecException
- if the given key specification is inappropriate for this secret-key
factory to produce a secret key.public final KeySpec getKeySpec(SecretKey key,
Class keySpec)
throws InvalidKeySpecException
key
- the keykeySpec
- the requested format
in which the key material shall be returned
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 SecretKey translateKey(SecretKey key)
throws InvalidKeyException
key
- the key whose provider
is unknown or untrusted
InvalidKeyException
- if the given key cannot be processed by this secret-key factory.
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