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 * 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.

 *

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package sun.security.rsa;

import java.io.IOException;

import java.security.*;

import java.security.spec.*;

import sun.security.util.ObjectIdentifier;

import sun.security.x509.AlgorithmId;

/**

 * Utility class for SunRsaSign provider.

 * Currently used by RSAKeyPairGenerator and RSAKeyFactory.

 *

 * @since   11

 */

public class RSAUtil {

    public enum KeyType {

        RSA ("RSA"),

        PSS ("RSASSA-PSS"),

        ;

        private final String algo;

        KeyType(String keyAlgo) {

            this.algo = keyAlgo;

        }

        public String keyAlgo() {

            return algo;

        }

        public static KeyType lookup(String name) {

            for (KeyType kt : KeyType.values()) {

                if (kt.keyAlgo().equalsIgnoreCase(name)) {

                    return kt;

                }

            }

            // no match

            throw new ProviderException("Unsupported algorithm " + name);

        }

    }

    public static void checkParamsAgainstType(KeyType type,

            AlgorithmParameterSpec paramSpec) throws ProviderException {

        switch (type) {

            case RSA:

                if (paramSpec != null) {

                    throw new ProviderException("null params expected for " +

                        type.keyAlgo());

                }

                break;

            case PSS:

                if ((paramSpec != null) &&

                    !(paramSpec instanceof PSSParameterSpec)) {

                    throw new ProviderException

                        ("PSSParmeterSpec expected for " + type.keyAlgo());

                }

                break;

            default:

                throw new ProviderException

                    ("Unsupported RSA algorithm " + type);

        }

    }

    public static AlgorithmId createAlgorithmId(KeyType type,

            AlgorithmParameterSpec paramSpec) throws ProviderException {

        checkParamsAgainstType(type, paramSpec);

        ObjectIdentifier oid = null;

        AlgorithmParameters params = null;

        try {

            switch (type) {

                case RSA:

                    oid = AlgorithmId.RSAEncryption_oid;

                    break;

                case PSS:

                    if (paramSpec != null) {

                        params = AlgorithmParameters.getInstance(type.keyAlgo());

                        params.init(paramSpec);

                    }

                    oid = AlgorithmId.RSASSA_PSS_oid;

                    break;

                default:

                    throw new ProviderException

                        ("Unsupported RSA algorithm "  + type);

            }

            AlgorithmId result;

            if (params == null) {

                result = new AlgorithmId(oid);

            } else {

                result = new AlgorithmId(oid, params);

            }

            return result;

        } catch (NoSuchAlgorithmException | InvalidParameterSpecException e) {

            // should not happen

            throw new ProviderException(e);

        }

    }

    public static AlgorithmParameterSpec getParamSpec(AlgorithmId algid)

            throws ProviderException {

        if (algid == null) {

            throw new ProviderException("AlgorithmId should not be null");

        }

        return getParamSpec(algid.getParameters());

    }

    public static AlgorithmParameterSpec getParamSpec(AlgorithmParameters params)

            throws ProviderException {

        if (params == null) return null;

        String algName = params.getAlgorithm();

        KeyType type = KeyType.lookup(algName);

        Class<? extends AlgorithmParameterSpec> specCls;

        switch (type) {

            case RSA:

                throw new ProviderException("No params accepted for " +

                    type.keyAlgo());

            case PSS:

                specCls = PSSParameterSpec.class;

                break;

            default:

                throw new ProviderException("Unsupported RSA algorithm: " + algName);

        }

        try {

            return params.getParameterSpec(specCls);

        } catch (Exception e) {

            throw new ProviderException(e);

        }

    }

}