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package java.security;

import java.security.spec.AlgorithmParameterSpec;


 This class defines the Service Provider Interface (SPI) for the KeyPairGenerator class, which is used to generate pairs of public and private keys. 
 All the abstract methods in this class must be implemented by each
cryptographic service provider who wishes to supply the implementation
of a key pair generator for a particular algorithm.

 In case the client does not explicitly initialize the KeyPairGenerator (via a call to an initialize method), each provider must supply (and document) a default initialization. See the Keysize Restriction sections of the {@extLink security_guide_jdk_providers JDK Providers} document for information on the KeyPairGenerator defaults used by JDK providers. 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 KeyPairGenerator instead of relying on provider-specific defaults. 
Author:Benjamin Renaud
See Also:
Since:1.2
/**
 * <p> This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
 * for the {@code KeyPairGenerator} class, which is used to generate
 * pairs of public and private keys.
 *
 * <p> All the abstract methods in this class must be implemented by each
 * cryptographic service provider who wishes to supply the implementation
 * of a key pair generator for a particular algorithm.
 *
 * <p> In case the client does not explicitly initialize the KeyPairGenerator
 * (via a call to an {@code initialize} method), each provider must
 * supply (and document) a default initialization.
 * See the Keysize Restriction sections of the
 * {@extLink security_guide_jdk_providers JDK Providers}
 * document for information on the KeyPairGenerator defaults used by
 * JDK providers.
 * 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
 * KeyPairGenerator instead of relying on provider-specific defaults.
 *
 * @author Benjamin Renaud
 * @since 1.2
 *
 *
 * @see KeyPairGenerator
 * @see java.security.spec.AlgorithmParameterSpec
 */

public abstract class KeyPairGeneratorSpi {

    
Initializes the key pair generator for a certain keysize, using
the default parameter set.

Params:
  • keysize – the keysize. This is an
algorithm-specific metric, such as modulus length, specified in
number of bits.
  • random – the source of randomness for this generator.
Throws:
/**
     * Initializes the key pair generator for a certain keysize, using
     * the default parameter set.
     *
     * @param keysize the keysize. This is an
     * algorithm-specific metric, such as modulus length, specified in
     * number of bits.
     *
     * @param random the source of randomness for this generator.
     *
     * @exception InvalidParameterException if the {@code keysize} is not
     * supported by this KeyPairGeneratorSpi object.
     */
    public abstract void initialize(int keysize, SecureRandom random);

    
Initializes the key pair generator using the specified parameter
set and user-provided source of randomness.

This concrete method has been added to this previously-defined
abstract class. (For backwards compatibility, it cannot be abstract.)
It may be overridden by a provider to initialize the key pair
generator. Such an override
is expected to throw an InvalidAlgorithmParameterException if
a parameter is inappropriate for this key pair generator.
If this method is not overridden, it always throws an
UnsupportedOperationException.

Params:
  • params – the parameter set used to generate the keys.
  • random – the source of randomness for this generator.
Throws:
Since:1.2
/**
     * Initializes the key pair generator using the specified parameter
     * set and user-provided source of randomness.
     *
     * <p>This concrete method has been added to this previously-defined
     * abstract class. (For backwards compatibility, it cannot be abstract.)
     * It may be overridden by a provider to initialize the key pair
     * generator. Such an override
     * is expected to throw an InvalidAlgorithmParameterException if
     * a parameter is inappropriate for this key pair generator.
     * If this method is not overridden, it always throws an
     * UnsupportedOperationException.
     *
     * @param params the parameter set used to generate the keys.
     *
     * @param random the source of randomness for this generator.
     *
     * @exception InvalidAlgorithmParameterException if the given parameters
     * are inappropriate for this key pair generator.
     *
     * @since 1.2
     */
    public void initialize(AlgorithmParameterSpec params,
                           SecureRandom random)
        throws InvalidAlgorithmParameterException {
            throw new UnsupportedOperationException();
    }

    
Generates a key pair. Unless an initialization method is called
using a KeyPairGenerator interface, algorithm-specific defaults
will be used. This will generate a new key pair every time it
is called.

Returns:the newly generated KeyPair
/**
     * Generates a key pair. Unless an initialization method is called
     * using a KeyPairGenerator interface, algorithm-specific defaults
     * will be used. This will generate a new key pair every time it
     * is called.
     *
     * @return the newly generated {@code KeyPair}
     */
    public abstract KeyPair generateKeyPair();
}