java.security: public class: AlgorithmParameters

java.security
public class: AlgorithmParameters [javadoc | source]

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.

Every implementation of the Java platform is required to support the following standard AlgorithmParameters algorithms:

AES
DES
DESede
DiffieHellman
DSA

These algorithms are described in the AlgorithmParameters section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other algorithms are supported.

Also see:

java.security.spec.AlgorithmParameterSpec

java.security.spec.DSAParameterSpec

KeyPairGenerator

author: Jan - Luehe

since: 1.2 -

Constructor:

Constructor:
protected AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm) { this.paramSpi = paramSpi; this.provider = provider; this.algorithm = algorithm; } Creates an AlgorithmParameters object. Parameters: `paramSpi` - the delegate `provider` - the provider `algorithm` - the algorithm

 protected AlgorithmParameters(AlgorithmParametersSpi paramSpi,
    Provider provider,
    String algorithm) {
        this.paramSpi = paramSpi;
        this.provider = provider;
        this.algorithm = algorithm;
}

Creates an AlgorithmParameters object.

Parameters:

paramSpi - the delegate

provider - the provider

algorithm - the algorithm

Method from java.security.AlgorithmParameters Summary:
getAlgorithm, getEncoded, getEncoded, getInstance, getInstance, getInstance, getParameterSpec, getProvider, init, init, init, toString

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from java.security.AlgorithmParameters Detail:
public final String getAlgorithm() { return this.algorithm; } Returns the name of the algorithm associated with this parameter object.
public final byte[] getEncoded() throws IOException { if (this.initialized == false) { throw new IOException("not initialized"); } return paramSpi.engineGetEncoded(); } 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.
public final byte[] getEncoded(String format) throws IOException { if (this.initialized == false) { throw new IOException("not initialized"); } return paramSpi.engineGetEncoded(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.
public static AlgorithmParameters getInstance(String algorithm) throws NoSuchAlgorithmException { try { Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters", (String)null); return new AlgorithmParameters((AlgorithmParametersSpi)objs[0], (Provider)objs[1], algorithm); } catch(NoSuchProviderException e) { throw new NoSuchAlgorithmException(algorithm + " not found"); } } 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.
public static AlgorithmParameters getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException { if (provider == null \|\| provider.length() == 0) throw new IllegalArgumentException("missing provider"); Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters", provider); return new AlgorithmParameters((AlgorithmParametersSpi)objs[0], (Provider)objs[1], algorithm); } 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.
public static AlgorithmParameters getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException { if (provider == null) throw new IllegalArgumentException("missing provider"); Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters", provider); return new AlgorithmParameters((AlgorithmParametersSpi)objs[0], (Provider)objs[1], algorithm); } 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.
public final T getParameterSpec(Class<T> paramSpec) throws InvalidParameterSpecException { if (this.initialized == false) { throw new InvalidParameterSpecException("not initialized"); } return paramSpi.engineGetParameterSpec(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.
public final Provider getProvider() { return this.provider; } Returns the provider of this parameter object.
public final void init(AlgorithmParameterSpec paramSpec) throws InvalidParameterSpecException { if (this.initialized) throw new InvalidParameterSpecException("already initialized"); paramSpi.engineInit(paramSpec); this.initialized = true; } Initializes this parameter object using the parameters specified in `paramSpec`.
public final void init(byte[] params) throws IOException { if (this.initialized) throw new IOException("already initialized"); paramSpi.engineInit(params); this.initialized = true; } 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.
public final void init(byte[] params, String format) throws IOException { if (this.initialized) throw new IOException("already initialized"); paramSpi.engineInit(params, format); this.initialized = true; } 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.
public final String toString() { if (this.initialized == false) { return null; } return paramSpi.engineToString(); } Returns a formatted string describing the parameters.

Method from java.security.AlgorithmParameters Detail:

 public final String getAlgorithm() {
        return this.algorithm;
}

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

 public final byte[] getEncoded() throws IOException {
        if (this.initialized == false) {
            throw new IOException("not initialized");
        }
        return paramSpi.engineGetEncoded();
}

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.

 public final byte[] getEncoded(String format) throws IOException {
        if (this.initialized == false) {
            throw new IOException("not initialized");
        }
        return paramSpi.engineGetEncoded(format);
}

format

 public static AlgorithmParameters getInstance(String algorithm) throws NoSuchAlgorithmException {
        try {
            Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters",
                                             (String)null);
            return new AlgorithmParameters((AlgorithmParametersSpi)objs[0],
                                           (Provider)objs[1],
                                           algorithm);
        } catch(NoSuchProviderException e) {
            throw new NoSuchAlgorithmException(algorithm + " not found");
        }
}

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.

 public static AlgorithmParameters getInstance(String algorithm,
    String provider) throws NoSuchAlgorithmException, NoSuchProviderException {
        if (provider == null || provider.length() == 0)
            throw new IllegalArgumentException("missing provider");
        Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters",
                                         provider);
        return new AlgorithmParameters((AlgorithmParametersSpi)objs[0],
                                       (Provider)objs[1],
                                       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.

 public static AlgorithmParameters getInstance(String algorithm,
    Provider provider) throws NoSuchAlgorithmException {
        if (provider == null)
            throw new IllegalArgumentException("missing provider");
        Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters",
                                         provider);
        return new AlgorithmParameters((AlgorithmParametersSpi)objs[0],
                                       (Provider)objs[1],
                                       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.

 public final T getParameterSpec(Class<T> paramSpec) throws InvalidParameterSpecException {
        if (this.initialized == false) {
            throw new InvalidParameterSpecException("not initialized");
        }
        return paramSpi.engineGetParameterSpec(paramSpec);
}

paramSpec

DSAParameterSpec.class

DSAParameterSpec

 public final Provider getProvider() {
        return this.provider;
}

Returns the provider of this parameter object.

 public final  void init(AlgorithmParameterSpec paramSpec) throws InvalidParameterSpecException {
        if (this.initialized)
            throw new InvalidParameterSpecException("already initialized");
        paramSpi.engineInit(paramSpec);
        this.initialized = true;
}

paramSpec

 public final  void init(byte[] params) throws IOException {
        if (this.initialized)
            throw new IOException("already initialized");
        paramSpi.engineInit(params);
        this.initialized = true;
}

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.

 public final  void init(byte[] params,
    String format) throws IOException {
        if (this.initialized)
            throw new IOException("already initialized");
        paramSpi.engineInit(params, format);
        this.initialized = true;
}

params

format

 public final String toString() {
        if (this.initialized == false) {
            return null;
        }
        return paramSpi.engineToString();
}

Returns a formatted string describing the parameters.