AlgorithmParameters

public class AlgorithmParameters extends Object

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.

Protected Constructor Summary

AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)
Creates an AlgorithmParameters object.

Public Method Summary

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 Method Summary

Protected Constructors

protected AlgorithmParameters (AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)

Creates an AlgorithmParameters object.

Parameters
paramSpi the delegate
provider the provider
algorithm the algorithm

Public Methods

public final String getAlgorithm ()

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

Returns
  • the algorithm name.

public final 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 the name of the encoding format.
Returns
  • the parameters encoded using the specified encoding scheme.
Throws
IOException on encoding errors, or if this parameter object has not been initialized.

public final 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
  • the parameters encoded using their primary encoding format.
Throws
IOException on encoding errors, or if this parameter object has not been initialized.

public static 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