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package javax.crypto;

import java.security.*;
import java.security.spec.*;


This class defines the Service Provider Interface (SPI)
for the KeyGenerator class.
All the abstract methods in this class must be implemented by each
cryptographic service provider who wishes to supply the implementation
of a key generator for a particular algorithm.

In case the client does not explicitly initialize the KeyGenerator (via a call to an init 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 KeyGenerator 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 KeyGenerator instead of relying on provider-specific defaults. 
Author:Jan Luehe
See Also:
Since:1.4
/**
 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
 * for the <code>KeyGenerator</code> class.
 * All the abstract methods in this class must be implemented by each
 * cryptographic service provider who wishes to supply the implementation
 * of a key generator for a particular algorithm.
 *
 * <p>In case the client does not explicitly initialize the KeyGenerator
 * (via a call to an {@code init} 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 KeyGenerator 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
 * KeyGenerator instead of relying on provider-specific defaults.
 *
 * @author Jan Luehe
 *
 * @see SecretKey
 * @since 1.4
 */

public abstract class KeyGeneratorSpi {

    
Constructor for subclasses to call.

/**
     * Constructor for subclasses to call.
     */
    public KeyGeneratorSpi() {}

    
Initializes the key generator.

Params:
  • random – the source of randomness for this generator
/**
     * Initializes the key generator.
     *
     * @param random the source of randomness for this generator
     */
    protected abstract void engineInit(SecureRandom random);

    
Initializes the key generator with the specified parameter
set and a user-provided source of randomness.

Params:
  • params – the key generation parameters
  • random – the source of randomness for this key generator
Throws:
/**
     * Initializes the key generator with the specified parameter
     * set and a user-provided source of randomness.
     *
     * @param params the key generation parameters
     * @param random the source of randomness for this key generator
     *
     * @exception InvalidAlgorithmParameterException if <code>params</code> is
     * inappropriate for this key generator
     */
    protected abstract void engineInit(AlgorithmParameterSpec params,
                                       SecureRandom random)
        throws InvalidAlgorithmParameterException;

    
Initializes this key generator for a certain keysize, using the given
source of randomness.

Params:
  • keysize – the keysize. This is an algorithm-specific metric,
specified in number of bits.
  • random – the source of randomness for this key generator
Throws:
/**
     * Initializes this key generator for a certain keysize, using the given
     * source of randomness.
     *
     * @param keysize the keysize. This is an algorithm-specific metric,
     * specified in number of bits.
     * @param random the source of randomness for this key generator
     *
     * @exception InvalidParameterException if the keysize is wrong or not
     * supported.
     */
    protected abstract void engineInit(int keysize, SecureRandom random);

    
Generates a secret key.

Returns:the new key
/**
     * Generates a secret key.
     *
     * @return the new key
     */
    protected abstract SecretKey engineGenerateKey();
}