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Added in API level 1

AlgorithmParameters

public class AlgorithmParameters
extends Object

java.lang.Object
   ↳ java.security.AlgorithmParameters


This class is used as an opaque representation of cryptographic parameters.

An AlgorithmParameters object for managing the parameters for a particular algorithm can be obtained by calling one of the getInstance factory methods (static methods that return instances of a given class).

Once an AlgorithmParameters object is obtained, it must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.

A transparent parameter specification is obtained from an AlgorithmParameters object via a call to getParameterSpec, and a byte encoding of the parameters is obtained via a call to getEncoded.

Android provides the following AlgorithmParameters algorithms:

Name Supported (API Levels)
AES 1+
Blowfish 10+
DES 1+
DESede 1+
DH 1+
DSA 1+
GCM 22+
IES 1–8
OAEP 1+
PKCS12PBE 1+
PSS 1–8, 24+
These algorithms are described in the AlgorithmParameters section of the Java Cryptography Architecture Standard Algorithm Name Documentation.

See also:

Summary

Protected constructors

AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)

Creates an AlgorithmParameters object.

Public methods

final String getAlgorithm()

Returns the name of the algorithm associated with this parameter object.

final byte[] getEncoded(String format)

Returns the parameters encoded in the specified scheme.

final byte[] getEncoded()

Returns the parameters in their primary encoding format.

static AlgorithmParameters getInstance(String algorithm)

Returns a parameter object for the specified algorithm.

static AlgorithmParameters getInstance(String algorithm, String provider)

Returns a parameter object for the specified algorithm.

static AlgorithmParameters getInstance(String algorithm, Provider provider)

Returns a parameter object for the specified algorithm.

final <T extends AlgorithmParameterSpec> T getParameterSpec(Class<T> paramSpec)

Returns a (transparent) specification of this parameter object.

final Provider getProvider()

Returns the provider of this parameter object.

final void init(byte[] params)

Imports the specified parameters and decodes them according to the primary decoding format for parameters.

final void init(AlgorithmParameterSpec paramSpec)

Initializes this parameter object using the parameters specified in paramSpec.

final void init(byte[] params, String format)

Imports the parameters from params and decodes them according to the specified decoding scheme.

final String toString()

Returns a formatted string describing the parameters.

Inherited methods

From class java.lang.Object

Protected constructors

AlgorithmParameters

Added in API level 1
AlgorithmParameters (AlgorithmParametersSpi paramSpi, 
                Provider provider, 
                String algorithm)

Creates an AlgorithmParameters object.

Parameters
paramSpi AlgorithmParametersSpi: the delegate
provider Provider: the provider
algorithm String: the algorithm

Public methods

getAlgorithm

Added in API level 1
String getAlgorithm ()

Returns the name of the algorithm associated with this parameter object.

Returns
String the algorithm name.

getEncoded

Added in API level 1
byte[] getEncoded (String format)

Returns the parameters encoded in the specified scheme. If format is null, the primary encoding format for parameters is used. The primary encoding format is ASN.1, if an ASN.1 specification for these parameters exists.

Parameters
format String: the name of the encoding format.
Returns
byte[] the parameters encoded using the specified encoding scheme.
Throws
IOException on encoding errors, or if this parameter object has not been initialized.

getEncoded

Added in API level 1
byte[] getEncoded ()

Returns the parameters in their primary encoding format. The primary encoding format for parameters is ASN.1, if an ASN.1 specification for this type of parameters exists.

Returns
byte[] the parameters encoded using their primary encoding format.
Throws
IOException on encoding errors, or if this parameter object has not been initialized.

getInstance

Added in API level 1
AlgorithmParameters getInstance (String algorithm)

Returns a parameter object for the specified algorithm.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi 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.

The returned parameter object must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.

Parameters
algorithm String: the name of the algorithm requested. See the AlgorithmParameters section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
Returns
AlgorithmParameters the new parameter object.
Throws
NoSuchAlgorithmException if no Provider supports an AlgorithmParametersSpi implementation for the specified algorithm.

See also:

getInstance

Added in API level 1
AlgorithmParameters getInstance (String algorithm, 
                String provider)

Returns a parameter object for the specified algorithm.

A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi 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.

The returned parameter object must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.

Parameters
algorithm String: the name of the algorithm requested. See the AlgorithmParameters section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
provider String: the name of the provider.
Returns
AlgorithmParameters the new parameter object.
Throws
NoSuchAlgorithmException if an AlgorithmParametersSpi 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.
IllegalArgumentException if the provider name is null or empty.

See also:

getInstance

Added in API level 1
AlgorithmParameters getInstance (String algorithm, 
                Provider provider)

Returns a parameter object for the specified algorithm.

A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.

The returned parameter object must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.

Parameters
algorithm String: the name of the algorithm requested. See the AlgorithmParameters section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
provider Provider: the name of the provider.
Returns
AlgorithmParameters the new parameter object.
Throws
NoSuchAlgorithmException if an AlgorithmParameterGeneratorSpi implementation for the specified algorithm is not available from the specified Provider object.
IllegalArgumentException if the provider is null.

See also:

getParameterSpec

Added in API level 1
T getParameterSpec (Class<T> paramSpec)

Returns a (transparent) specification of this parameter object. paramSpec identifies the specification class in which the parameters should be returned. It could, for example, be DSAParameterSpec.class, to indicate that the parameters should be returned in an instance of the DSAParameterSpec class.

Parameters
paramSpec Class: the specification class in which the parameters should be returned.
Returns
T the parameter specification.
Throws
InvalidParameterSpecException if the requested parameter specification is inappropriate for this parameter object, or if this parameter object has not been initialized.

getProvider

Added in API level 1
Provider getProvider ()

Returns the provider of this parameter object.

Returns
Provider the provider of this parameter object

init

Added in API level 1
void init (byte[] params)

Imports the specified parameters and decodes them according to the primary decoding format for parameters. The primary decoding format for parameters is ASN.1, if an ASN.1 specification for this type of parameters exists.

Parameters
params byte: the encoded parameters.
Throws
IOException on decoding errors, or if this parameter object has already been initialized.

init

Added in API level 1
void init (AlgorithmParameterSpec paramSpec)

Initializes this parameter object using the parameters specified in paramSpec.

Parameters
paramSpec AlgorithmParameterSpec: the parameter specification.
Throws
InvalidParameterSpecException if the given parameter specification is inappropriate for the initialization of this parameter object, or if this parameter object has already been initialized.

init

Added in API level 1
void init (byte[] params, 
                String format)

Imports the parameters from params and decodes them according to the specified decoding scheme. If format is null, the primary decoding format for parameters is used. The primary decoding format is ASN.1, if an ASN.1 specification for these parameters exists.

Parameters
params byte: the encoded parameters.
format String: the name of the decoding scheme.
Throws
IOException on decoding errors, or if this parameter object has already been initialized.

toString

Added in API level 1
String toString ()

Returns a formatted string describing the parameters.

Returns
String a formatted string describing the parameters, or null if this parameter object has not been initialized.
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