Class AlgorithmParameters

java.lang.Object
java.security.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.

Every implementation of the Java platform is required to support the following standard AlgorithmParameters algorithms. For the "EC" algorithm, implementations must support the curves in parentheses. For the "RSASSA-PSS" algorithm, implementations must support the parameters in parentheses.

  • AES
  • ChaCha20-Poly1305
  • DiffieHellman
  • DSA
  • EC (secp256r1, secp384r1)
  • PBEWithHmacSHA256AndAES_128
  • PBEWithHmacSHA256AndAES_256
  • RSASSA-PSS (MGF1 mask generation function and SHA-256 or SHA-384 hash algorithms)
These algorithms are described in the AlgorithmParameters section of the Java Security Standard Algorithm Names Specification. Consult the release documentation for your implementation to see if any other algorithms are supported.
Since:
1.2
External Specifications
See Also:

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)
    Creates an AlgorithmParameters object.

  • Method Summary

    Modifier and Type
    Method
    Description
    final String
    getAlgorithm()
    Returns the name of the algorithm associated with this parameter object.
    final byte[]
    getEncoded()
    Returns the parameters in their primary encoding format.
    final byte[]
    getEncoded(String format)
    Returns the parameters encoded in the specified scheme.
    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(byte[] params, String format)
    Imports the parameters from params and decodes them according to the specified decoding scheme.
    final void
    init(AlgorithmParameterSpec paramSpec)
    Initializes this parameter object using the parameters specified in paramSpec.
    final String
    toString()
    Returns a formatted string describing the parameters.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Creates and returns a copy of this object.
    boolean
    equals(Object obj)
    Indicates whether some other object is "equal to" this one.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Finalization is deprecated and subject to removal in a future release.
    final Class<?>
    getClass()
    Returns the runtime class of this Object.
    int
    hashCode()
    Returns a hash code value for this 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.
    final void
    wait()
    Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
    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(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.

  • Constructor Details

    • AlgorithmParameters

      protected AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)
      Creates an AlgorithmParameters object.
      Parameters:
      paramSpi - the delegate
      provider - the provider
      algorithm - the algorithm

  • Method Details

    • getAlgorithm

      public final String getAlgorithm()
      Returns the name of the algorithm associated with this parameter object.
      Returns:
      the algorithm name.

    • getInstance

      public static AlgorithmParameters getInstance(String algorithm) throws NoSuchAlgorithmException
      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.

      Implementation Note:
      The JDK Reference Implementation additionally uses the jdk.security.provider.preferred Security property to determine the preferred provider order for the specified algorithm. This may be different from the order of providers returned by Security.getProviders().
      Parameters:
      algorithm - the name of the algorithm requested. See the AlgorithmParameters section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
      Returns:
      the new parameter object
      Throws:
      NoSuchAlgorithmException - if no Provider supports an AlgorithmParametersSpi implementation for the specified algorithm
      NullPointerException - if algorithm is null
      External Specifications
      See Also:

    • getInstance

      public static AlgorithmParameters getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException
      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 - the name of the algorithm requested. See the AlgorithmParameters section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
      provider - the name of the provider.
      Returns:
      the new parameter object
      Throws:
      IllegalArgumentException - if the provider name is null or empty
      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
      NullPointerException - if algorithm is null
      External Specifications
      See Also:

    • getInstance

      public static AlgorithmParameters getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException
      Returns a parameter object for the specified algorithm.

      A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi implementation from the specified provider is returned. Note that the specified provider 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 - the name of the algorithm requested. See the AlgorithmParameters section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.
      provider - the name of the provider.
      Returns:
      the new parameter object
      Throws:
      IllegalArgumentException - if the 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
      Since:
      1.4
      External Specifications
      See Also:

    • getProvider

      public final Provider getProvider()
      Returns the provider of this parameter object.
      Returns:
      the provider of this parameter object

    • init

      public final void init(AlgorithmParameterSpec paramSpec) throws InvalidParameterSpecException
      Initializes this parameter object using the parameters specified in paramSpec.
      Parameters:
      paramSpec - 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

      public final void init(byte[] params) throws IOException
      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 - the encoded parameters.
      Throws:
      IOException - on decoding errors, or if this parameter object has already been initialized.

    • init

      public final void init(byte[] params, String format) throws IOException
      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 - the encoded parameters.
      format - the name of the decoding scheme.
      Throws:
      IOException - on decoding errors, or if this parameter object has already been initialized.

    • getParameterSpec

      public final <T extends AlgorithmParameterSpec> T getParameterSpec(Class<T> paramSpec) throws InvalidParameterSpecException
      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.
      Type Parameters:
      T - the type of the parameter specification to be returned
      Parameters:
      paramSpec - the specification class in which the parameters should be returned.
      Returns:
      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.

    • getEncoded

      public final byte[] getEncoded() throws IOException
      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.

    • getEncoded

      public final byte[] getEncoded(String format) throws IOException
      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.

    • toString

      public final String toString()
      Returns a formatted string describing the parameters.
      Overrides:
      toString in class Object
      Returns:
      a formatted string describing the parameters, or null if this parameter object has not been initialized.