public
class
SecretKeyFactory
extends Object
java.lang.Object | |
↳ | javax.crypto.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.
Android provides the following SecretKeyFactory
algorithms:
Name | Supported (API Levels) |
---|---|
AES | 23+ |
DES | 1+ |
DESede | 1+ |
HmacSHA1 | 23+ |
HmacSHA224 | 23+ |
HmacSHA256 | 23+ |
HmacSHA384 | 23+ |
HmacSHA512 | 23+ |
PBEwithHmacSHA1 | 1+ |
PBEwithMD5and128BITAES-CBC-OPENSSL | 1+ |
PBEwithMD5and192BITAES-CBC-OPENSSL | 1+ |
PBEwithMD5and256BITAES-CBC-OPENSSL | 1+ |
PBEwithMD5andDES | 1+ |
PBEwithMD5andRC2 | 1+ |
PBEwithSHA1andDES | 1+ |
PBEwithSHA1andRC2 | 1+ |
PBEwithSHA256and128BITAES-CBC-BC | 1+ |
PBEwithSHA256and192BITAES-CBC-BC | 1+ |
PBEwithSHA256and256BITAES-CBC-BC | 1+ |
PBEwithSHAand128BITAES-CBC-BC | 1+ |
PBEwithSHAand128BITRC2-CBC | 10+ |
PBEwithSHAand128BITRC4 | 10+ |
PBEwithSHAand192BITAES-CBC-BC | 1+ |
PBEwithSHAand2-KEYTRIPLEDES-CBC | 1+ |
PBEwithSHAand256BITAES-CBC-BC | 1+ |
PBEwithSHAand3-KEYTRIPLEDES-CBC | 1+ |
PBEwithSHAand40BITRC2-CBC | 1+ |
PBEwithSHAand40BITRC4 | 10+ |
PBEwithSHAandTWOFISH-CBC | 10+ |
PBKDF2withHmacSHA1 | 10+ |
PBKDF2withHmacSHA1and8BIT | 19+ |
Protected constructors | |
---|---|
SecretKeyFactory(SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm)
Creates a SecretKeyFactory object. |
Public methods | |
---|---|
final
SecretKey
|
generateSecret(KeySpec keySpec)
Generates a |
final
String
|
getAlgorithm()
Returns the algorithm name of this |
static
final
SecretKeyFactory
|
getInstance(String algorithm)
Returns a |
static
final
SecretKeyFactory
|
getInstance(String algorithm, String provider)
Returns a |
static
final
SecretKeyFactory
|
getInstance(String algorithm, Provider provider)
Returns a |
final
KeySpec
|
getKeySpec(SecretKey key, Class keySpec)
Returns a specification (key material) of the given key object in the requested format. |
final
Provider
|
getProvider()
Returns the provider of this |
final
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. |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
SecretKeyFactory (SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm)
Creates a SecretKeyFactory object.
Parameters | |
---|---|
keyFacSpi |
SecretKeyFactorySpi :
the delegate |
provider |
Provider :
the provider |
algorithm |
String :
the secret-key algorithm
|
SecretKey generateSecret (KeySpec keySpec)
Generates a SecretKey
object from the provided key
specification (key material).
Parameters | |
---|---|
keySpec |
KeySpec :
the specification (key material) of the secret key |
Returns | |
---|---|
SecretKey |
the secret key |
Throws | |
---|---|
InvalidKeySpecException |
if the given key specification is inappropriate for this secret-key factory to produce a secret key. |
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 | |
---|---|
String |
the algorithm name of this SecretKeyFactory
object.
|
SecretKeyFactory getInstance (String algorithm)
Returns a SecretKeyFactory
object 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.
Parameters | |
---|---|
algorithm |
String :
the standard name of the requested secret-key
algorithm.
See the SecretKeyFactory section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
for information about standard algorithm names. |
Returns | |
---|---|
SecretKeyFactory |
the new SecretKeyFactory object. |
Throws | |
---|---|
NullPointerException |
if the specified algorithm is null. |
NoSuchAlgorithmException |
if no Provider supports a SecretKeyFactorySpi implementation for the specified algorithm. |
See also:
SecretKeyFactory getInstance (String algorithm, String provider)
Returns a SecretKeyFactory
object 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 |
String :
the standard name of the requested secret-key
algorithm.
See the SecretKeyFactory section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
for information about standard algorithm names. |
provider |
String :
the name of the provider. |
Returns | |
---|---|
SecretKeyFactory |
the new SecretKeyFactory object. |
Throws | |
---|---|
NoSuchAlgorithmException |
if a SecretKeyFactorySpi implementation for the specified algorithm is not available from the specified provider. |
NullPointerException |
if the specified algorithm is null. |
NoSuchProviderException |
if the specified provider is not registered in the security provider list. |
IllegalArgumentException |
if the provider
is null or empty. |
See also:
SecretKeyFactory getInstance (String algorithm, Provider provider)
Returns a SecretKeyFactory
object 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 |
String :
the standard name of the requested secret-key
algorithm.
See the SecretKeyFactory section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
for information about standard algorithm names. |
provider |
Provider :
the provider. |
Returns | |
---|---|
SecretKeyFactory |
the new SecretKeyFactory object. |
Throws | |
---|---|
NullPointerException |
if the specified algorithm is null. |
NoSuchAlgorithmException |
if a SecretKeyFactorySpi implementation for the specified algorithm is not available from the specified Provider object. |
IllegalArgumentException |
if the provider
is null. |
See also:
KeySpec getKeySpec (SecretKey key, Class keySpec)
Returns a specification (key material) of the given key object in the requested format.
Parameters | |
---|---|
key |
SecretKey :
the key |
keySpec |
Class :
the requested format in which the key material shall be
returned |
Returns | |
---|---|
KeySpec |
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
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).
|
Provider getProvider ()
Returns the provider of this SecretKeyFactory
object.
Returns | |
---|---|
Provider |
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.
Parameters | |
---|---|
key |
SecretKey :
the key whose provider is unknown or untrusted |
Returns | |
---|---|
SecretKey |
the translated key |
Throws | |
---|---|
InvalidKeyException |
if the given key cannot be processed by this secret-key factory. |