/*

 * Copyright (c) 1998, 2005, 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

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 */

package java.security;

/**

 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)

 * for the <code>SecureRandom</code> class.

 * All the abstract methods in this class must be implemented by each

 * service provider who wishes to supply the implementation

 * of a cryptographically strong pseudo-random number generator.

 *

 *

 * @see SecureRandom

 * @since 1.2

 */

public abstract class SecureRandomSpi implements java.io.Serializable {

    private static final long serialVersionUID = -2991854161009191830L;

    /**

     * Reseeds this random object. The given seed supplements, rather than

     * replaces, the existing seed. Thus, repeated calls are guaranteed

     * never to reduce randomness.

     *

     * @param seed the seed.

     */

    protected abstract void engineSetSeed(byte[] seed);

    /**

     * Generates a user-specified number of random bytes.

     *

     * <p> If a call to <code>engineSetSeed</code> had not occurred previously,

     * the first call to this method forces this SecureRandom implementation

     * to seed itself.  This self-seeding will not occur if

     * <code>engineSetSeed</code> was previously called.

     *

     * @param bytes the array to be filled in with random bytes.

     */

    protected abstract void engineNextBytes(byte[] bytes);

    /**

     * Returns the given number of seed bytes.  This call may be used to

     * seed other random number generators.

     *

     * @param numBytes the number of seed bytes to generate.

     *

     * @return the seed bytes.

     */

     protected abstract byte[] engineGenerateSeed(int numBytes);

}