/*

 * 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 com.sun.crypto.provider;

import java.security.*;

import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.*;

import javax.crypto.spec.SecretKeySpec;

/**

 * KeyGeneratore core implementation and individual key generator

 * implementations. Because of US export regulations, we cannot use

 * subclassing to achieve code sharing between the key generator

 * implementations for our various algorithms. Instead, we have the

 * core implementation in this KeyGeneratorCore class, which is used

 * by the individual implementations. See those further down in this

 * file.

 *

 * @since   1.5

 * @author  Andreas Sterbenz

 */

final class KeyGeneratorCore {

    // algorithm name to use for the generator keys

    private final String name;

    // default key size in bits

    private final int defaultKeySize;

    // current key size in bits

    private int keySize;

    // PRNG to use

    private SecureRandom random;

    /**

     * Construct a new KeyGeneratorCore object with the specified name

     * and defaultKeySize. Initialize to default key size in case the

     * application does not call any of the init() methods.

     */

    KeyGeneratorCore(String name, int defaultKeySize) {

        this.name = name;

        this.defaultKeySize = defaultKeySize;

        implInit(null);

    }

    // implementation for engineInit(), see JCE doc

    // reset keySize to default

    void implInit(SecureRandom random) {

        this.keySize = defaultKeySize;

        this.random = random;

    }

    // implementation for engineInit(), see JCE doc

    // we do not support any parameters

    void implInit(AlgorithmParameterSpec params, SecureRandom random)

            throws InvalidAlgorithmParameterException {

        throw new InvalidAlgorithmParameterException

            (name + " key generation does not take any parameters");

    }

    // implementation for engineInit(), see JCE doc

    // we enforce a general 40 bit minimum key size for security

    void implInit(int keysize, SecureRandom random) {

        if (keysize < 40) {

            throw new InvalidParameterException

                ("Key length must be at least 40 bits");

        }

        this.keySize = keysize;

        this.random = random;

    }

    // implementation for engineInit(), see JCE doc

    // generate the key

    SecretKey implGenerateKey() {

        if (random == null) {

        }

        byte[] b = new byte[(keySize + 7) >> 3];

        random.nextBytes(b);

        return new SecretKeySpec(b, name);

    }

    // nested static classes for the HmacSHA-2 family of key generator

    abstract static class HmacSHA2KG extends KeyGeneratorSpi {

        private final KeyGeneratorCore core;

        protected HmacSHA2KG(String algoName, int len) {

            core = new KeyGeneratorCore(algoName, len);

        }

        protected void engineInit(SecureRandom random) {

            core.implInit(random);

        }

        protected void engineInit(AlgorithmParameterSpec params,

                SecureRandom random) throws InvalidAlgorithmParameterException {

            core.implInit(params, random);

        }

        protected void engineInit(int keySize, SecureRandom random) {

            core.implInit(keySize, random);

        }

        protected SecretKey engineGenerateKey() {

            return core.implGenerateKey();

        }

        public static final class SHA224 extends HmacSHA2KG {

            public SHA224() {

                super("HmacSHA224", 224);

            }

        }

        public static final class SHA256 extends HmacSHA2KG {

            public SHA256() {

                super("HmacSHA256", 256);

            }

        }

        public static final class SHA384 extends HmacSHA2KG {

            public SHA384() {

                super("HmacSHA384", 384);

            }

        }

        public static final class SHA512 extends HmacSHA2KG {

            public SHA512() {

                super("HmacSHA512", 512);

            }

        }

    }

    // nested static class for the RC2 key generator

    public static final class RC2KeyGenerator extends KeyGeneratorSpi {

        private final KeyGeneratorCore core;

        public RC2KeyGenerator() {

            core = new KeyGeneratorCore("RC2", 128);

        }

        protected void engineInit(SecureRandom random) {

            core.implInit(random);

        }

        protected void engineInit(AlgorithmParameterSpec params,

                SecureRandom random) throws InvalidAlgorithmParameterException {

            core.implInit(params, random);

        }

        protected void engineInit(int keySize, SecureRandom random) {

            if ((keySize < 40) || (keySize > 1024)) {

                throw new InvalidParameterException("Key length for RC2"

                    + " must be between 40 and 1024 bits");

            }

            core.implInit(keySize, random);

        }

        protected SecretKey engineGenerateKey() {

            return core.implGenerateKey();

        }

    }

    // nested static class for the ARCFOUR (RC4) key generator

    public static final class ARCFOURKeyGenerator extends KeyGeneratorSpi {

        private final KeyGeneratorCore core;

        public ARCFOURKeyGenerator() {

            core = new KeyGeneratorCore("ARCFOUR", 128);

        }

        protected void engineInit(SecureRandom random) {

            core.implInit(random);

        }

        protected void engineInit(AlgorithmParameterSpec params,

                SecureRandom random) throws InvalidAlgorithmParameterException {

            core.implInit(params, random);

        }

        protected void engineInit(int keySize, SecureRandom random) {

            if ((keySize < 40) || (keySize > 1024)) {

                throw new InvalidParameterException("Key length for ARCFOUR"

                    + " must be between 40 and 1024 bits");

            }

            core.implInit(keySize, random);

        }

        protected SecretKey engineGenerateKey() {

            return core.implGenerateKey();

        }

    }

}