Added in API level 1

Summary: Protected Ctors | Methods | Inherited Methods

AlgorithmParameterGenerator

public class AlgorithmParameterGenerator
extends Object

java.lang.Object
↳	java.security.AlgorithmParameterGenerator

The AlgorithmParameterGenerator class is used to generate a set of parameters to be used with a certain algorithm. Parameter generators are constructed using the getInstance factory methods (static methods that return instances of a given class).

The object that will generate the parameters can be initialized in two different ways: in an algorithm-independent manner, or in an algorithm-specific manner:

The algorithm-independent approach uses the fact that all parameter generators share the concept of a "size" and a source of randomness. The measure of size is universally shared by all algorithm parameters, though it is interpreted differently for different algorithms. For example, in the case of parameters for the DSA algorithm, "size" corresponds to the size of the prime modulus (in bits). When using this approach, algorithm-specific parameter generation values - if any - default to some standard values, unless they can be derived from the specified size.
The other approach initializes a parameter generator object using algorithm-specific semantics, which are represented by a set of algorithm-specific parameter generation values. To generate Diffie-Hellman system parameters, for example, the parameter generation values usually consist of the size of the prime modulus and the size of the random exponent, both specified in number of bits.

In case the client does not explicitly initialize the AlgorithmParameterGenerator (via a call to an init method), each provider must supply (and document) a default initialization. However, note that defaults may vary across different providers. Additionally, the default value for a provider may change in a future version. Therefore, it is recommended to explicitly initialize the AlgorithmParameterGenerator instead of relying on provider-specific defaults.

Android provides the following AlgorithmParameterGenerator algorithms:

Algorithm	Supported API Levels
AES	1-8
DES	1-8
DESede	1-8
DH	1+
DSA	1+

See also:

Summary

Protected constructors
`AlgorithmParameterGenerator(AlgorithmParameterGeneratorSpi paramGenSpi, Provider provider, String algorithm)` Creates an AlgorithmParameterGenerator object.

Public methods
`final AlgorithmParameters`	`generateParameters()` Generates the parameters.
`final String`	`getAlgorithm()` Returns the standard name of the algorithm this parameter generator is associated with.
`static AlgorithmParameterGenerator`	`getInstance(String algorithm)` Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.
`static AlgorithmParameterGenerator`	`getInstance(String algorithm, String provider)` Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.
`static AlgorithmParameterGenerator`	`getInstance(String algorithm, Provider provider)` Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.
`final Provider`	`getProvider()` Returns the provider of this algorithm parameter generator object.
`final void`	`init(AlgorithmParameterSpec genParamSpec, SecureRandom random)` Initializes this parameter generator with a set of algorithm-specific parameter generation values.
`final void`	`init(int size)` Initializes this parameter generator for a certain size.
`final void`	`init(int size, SecureRandom random)` Initializes this parameter generator for a certain size and source of randomness.
`final void`	`init(AlgorithmParameterSpec genParamSpec)` Initializes this parameter generator with a set of algorithm-specific parameter generation values.

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

AlgorithmParameterGenerator

Added in API level 1

protected AlgorithmParameterGenerator (AlgorithmParameterGeneratorSpi paramGenSpi, 
                Provider provider, 
                String algorithm)

Creates an AlgorithmParameterGenerator object.

Parameters
`paramGenSpi`	`AlgorithmParameterGeneratorSpi`: the delegate
`provider`	`Provider`: the provider
`algorithm`	`String`: the algorithm

Public methods

generateParameters

Added in API level 1

public final AlgorithmParameters generateParameters ()

Generates the parameters.

Returns
`AlgorithmParameters`	the new AlgorithmParameters object.

getAlgorithm

Added in API level 1

public final String getAlgorithm ()

Returns the standard name of the algorithm this parameter generator is associated with.

Returns
`String`	the string name of the algorithm.

getInstance

Added in API level 1

public static AlgorithmParameterGenerator getInstance (String algorithm)

Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new AlgorithmParameterGenerator object encapsulating the AlgorithmParameterGeneratorSpi 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 name of the algorithm this parameter generator is associated with.cc

Returns
`AlgorithmParameterGenerator`	the new `AlgorithmParameterGenerator` object

Throws
`NoSuchAlgorithmException`	if no `Provider` supports an `AlgorithmParameterGeneratorSpi` implementation for the specified algorithm
`NullPointerException`	if `algorithm` is `null` on Android 14 or above

See also:

Provider

getInstance

Added in API level 1

public static AlgorithmParameterGenerator getInstance (String algorithm, 
                String provider)

Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.

A new AlgorithmParameterGenerator object encapsulating the AlgorithmParameterGeneratorSpi 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 name of the algorithm this parameter generator is associated with.
`provider`	`String`: the string name of the Provider.

Returns
`AlgorithmParameterGenerator`	the new `AlgorithmParameterGenerator` object

Throws
`IllegalArgumentException`	if the provider name is `null` or empty
`NoSuchAlgorithmException`	if an `AlgorithmParameterGeneratorSpi` implementation 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 `algorithm` is `null` on Android 14 or above

See also:

Provider

getInstance

Added in API level 1

public static AlgorithmParameterGenerator getInstance (String algorithm, 
                Provider provider)

Returns an AlgorithmParameterGenerator object for generating a set of parameters to be used with the specified algorithm.

A new AlgorithmParameterGenerator object encapsulating the AlgorithmParameterGeneratorSpi 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 string name of the algorithm this parameter generator is associated with.
`provider`	`Provider`: the `Provider` object.

Returns
`AlgorithmParameterGenerator`	the new `AlgorithmParameterGenerator` object

Throws
`IllegalArgumentException`	if the specified provider is `null`
`NoSuchAlgorithmException`	if an `AlgorithmParameterGeneratorSpi` implementation for the specified algorithm is not available from the specified `Provider` object
`NullPointerException`	if `algorithm` is `null` on Android 14 or above

See also:

Provider

getProvider

Added in API level 1

public final Provider getProvider ()

Returns the provider of this algorithm parameter generator object.

Returns
`Provider`	the provider of this algorithm parameter generator object

init

Added in API level 1

public final void init (AlgorithmParameterSpec genParamSpec, 
                SecureRandom random)

Initializes this parameter generator with a set of algorithm-specific parameter generation values.

Parameters
`genParamSpec`	`AlgorithmParameterSpec`: the set of algorithm-specific parameter generation values.
`random`	`SecureRandom`: the source of randomness.

Throws
`InvalidAlgorithmParameterException`	if the given parameter generation values are inappropriate for this parameter generator.

init

Added in API level 1

public final void init (int size)

Initializes this parameter generator for a certain size. To create the parameters, the SecureRandom implementation of the highest-priority installed provider is used as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness is used.)

Parameters
`size`	`int`: the size (number of bits).

init

Added in API level 1

public final void init (int size, 
                SecureRandom random)

Initializes this parameter generator for a certain size and source of randomness.

Parameters
`size`	`int`: the size (number of bits).
`random`	`SecureRandom`: the source of randomness.

init

Added in API level 1

public final void init (AlgorithmParameterSpec genParamSpec)

Initializes this parameter generator with a set of algorithm-specific parameter generation values. To generate the parameters, the SecureRandom implementation of the highest-priority installed provider is used as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness is used.)

Parameters
`genParamSpec`	`AlgorithmParameterSpec`: the set of algorithm-specific parameter generation values.

Throws
`InvalidAlgorithmParameterException`	if the given parameter generation values are inappropriate for this parameter generator.