Added in API level 1

Summary: Protected Ctors | Methods | Inherited Methods

SecretKeyFactory

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:

Algorithm	Supported API Levels
AES	23+
DES	1+
DESede	1+
HmacSHA1	23+
HmacSHA224	23+
HmacSHA256	23+
HmacSHA384	23+
HmacSHA512	23+
PBEwithHmacSHA1	1+
PBEwithHmacSHA1AndAES_128	26+
PBEwithHmacSHA1AndAES_256	26+
PBEwithHmacSHA224AndAES_128	26+
PBEwithHmacSHA224AndAES_256	26+
PBEwithHmacSHA256AndAES_128	26+
PBEwithHmacSHA256AndAES_256	26+
PBEwithHmacSHA384AndAES_128	26+
PBEwithHmacSHA384AndAES_256	26+
PBEwithHmacSHA512AndAES_128	26+
PBEwithHmacSHA512AndAES_256	26+
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+
PBKDF2withHmacSHA224	26+
PBKDF2withHmacSHA256	26+
PBKDF2withHmacSHA384	26+
PBKDF2withHmacSHA512	26+

These algorithms are described in the SecretKeyFactory section of the Java Cryptography Architecture Standard Algorithm Name Documentation.

See also:

Summary

Protected constructors
`SecretKeyFactory(SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm)` Creates a SecretKeyFactory object.

Public methods
`final SecretKey`	`generateSecret(KeySpec keySpec)` Generates a `SecretKey` object from the provided key specification (key material).
`final String`	`getAlgorithm()` Returns the algorithm name of this `SecretKeyFactory` object.
`static final SecretKeyFactory`	`getInstance(String algorithm)` Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm.
`static final SecretKeyFactory`	`getInstance(String algorithm, String provider)` Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm.
`static final SecretKeyFactory`	`getInstance(String algorithm, Provider provider)` Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm.
`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 `SecretKeyFactory` object.
`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

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Protected constructors

SecretKeyFactory

Added in API level 1

protected 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

Public methods

generateSecret

Added in API level 1

public final 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.

getAlgorithm

Added in API level 1

public final 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.

getInstance

Added in API level 1

public static final 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:

Provider

getInstance

Added in API level 1

public static final 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:

Provider

getInstance

Added in API level 1

public static final 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:

Provider

getKeySpec

Added in API level 1

public final 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).

getProvider

Added in API level 1

public final Provider getProvider ()

Returns the provider of this SecretKeyFactory object.

Returns
`Provider`	the provider of this `SecretKeyFactory` object

translateKey

Added in API level 1

public 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.

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.