/*

 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.security.interfaces;

import java.security.*;

/**

 * An interface to an object capable of generating DSA key pairs.

 *

 * <p>The {@code initialize} methods may each be called any number

 * of times. If no {@code initialize} method is called on a

 * DSAKeyPairGenerator, each provider that implements this interface

 * should supply (and document) a default initialization. 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 DSAKeyPairGenerator instead

 * of relying on provider-specific defaults.

 *

 * <p>Users wishing to indicate DSA-specific parameters, and to generate a key

 * pair suitable for use with the DSA algorithm typically

 *

 * <ol>

 *

 * <li>Get a key pair generator for the DSA algorithm by calling the

 * KeyPairGenerator {@code getInstance} method with "DSA"

 * as its argument.

 *

 * <li>Check if the returned key pair generator is an instance of

 * DSAKeyPairGenerator before casting the result to a DSAKeyPairGenerator

 * and calling one of the {@code initialize} methods from this

 * DSAKeyPairGenerator interface.

 *

 * <li>Generate a key pair by calling the {@code generateKeyPair}

 * method of the KeyPairGenerator class.

 *

 * </ol>

 *

 * <p>Note: it is not always necessary to do algorithm-specific

 * initialization for a DSA key pair generator. That is, it is not always

 * necessary to call an {@code initialize} method in this interface.

 * Algorithm-independent initialization using the {@code initialize} method

 * in the KeyPairGenerator

 * interface is all that is needed when you accept defaults for algorithm-specific

 * parameters.

 *

 * <p>Note: Some earlier implementations of this interface may not support

 * larger values of DSA parameters such as 3072-bit.

 *

 * @since 1.1

 * @see java.security.KeyPairGenerator

 */

public interface DSAKeyPairGenerator {

    /**

     * Initializes the key pair generator using the DSA family parameters

     * (p,q and g) and an optional SecureRandom bit source. If a

     * SecureRandom bit source is needed but not supplied, i.e. null, a

     * default SecureRandom instance will be used.

     *

     * @param params the parameters to use to generate the keys.

     *

     * @param random the random bit source to use to generate key bits;

     * can be null.

     *

     * @throws    InvalidParameterException if the {@code params}

     * value is invalid, null, or unsupported.

     */

   public void initialize(DSAParams params, SecureRandom random)

   throws InvalidParameterException;

    /**

     * Initializes the key pair generator for a given modulus length

     * (instead of parameters), and an optional SecureRandom bit source.

     * If a SecureRandom bit source is needed but not supplied, i.e.

     * null, a default SecureRandom instance will be used.

     *

     * <p>If {@code genParams} is true, this method generates new

     * p, q and g parameters. If it is false, the method uses precomputed

     * parameters for the modulus length requested. If there are no

     * precomputed parameters for that modulus length, an exception will be

     * thrown.

     *

     * @param modlen the modulus length in bits. Valid values are any

     * multiple of 64 between 512 and 1024, inclusive, 2048, and 3072.

     *

     * @param random the random bit source to use to generate key bits;

     * can be null.

     *

     * @param genParams whether or not to generate new parameters for

     * the modulus length requested.

     *

     * @throws    InvalidParameterException if {@code modlen} is

     * invalid, or unsupported, or if {@code genParams} is false and there

     * are no precomputed parameters for the requested modulus length.

     */

    public void initialize(int modlen, boolean genParams, SecureRandom random)

    throws InvalidParameterException;

}