Generates a key pair.

  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

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

  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.
Parameters:
- params - the parameter set used to generate the keys.
- random - the source of randomness for this generator.
Throws:
- InvalidAlgorithmParameterException - if the given parameters are inappropriate for this key pair generator.
Since: 1.2

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

  Initializes the key pair generator for a certain keysize, using
the default parameter set.
Parameters:
- 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:
- InvalidParameterException - if the keysize is not supported by this KeyPairGeneratorSpi object.