GordianGOSTEncodedParser.java

/*
 * GordianKnot: Security Suite
 * Copyright 2026. Tony Washer
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.  You may obtain a copy
 * of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package io.github.tonywasher.joceanus.gordianknot.impl.core.keypair.parser;

import io.github.tonywasher.joceanus.gordianknot.api.base.GordianException;
import io.github.tonywasher.joceanus.gordianknot.api.keypair.spec.GordianKeyPairSpec;
import io.github.tonywasher.joceanus.gordianknot.impl.core.exc.GordianDataException;
import io.github.tonywasher.joceanus.gordianknot.impl.core.spec.keypair.GordianCoreGOSTSpec;
import io.github.tonywasher.joceanus.gordianknot.impl.core.spec.keypair.GordianCoreKeyPairSpecBuilder;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.cryptopro.ECGOST3410NamedCurves;
import org.bouncycastle.asn1.cryptopro.GOST3410PublicKeyAlgParameters;
import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
import org.bouncycastle.asn1.rosstandart.RosstandartObjectIdentifiers;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;

/**
 * GOST Encoded parser.
 */
public final class GordianGOSTEncodedParser implements GordianEncodedParser {
    /**
     * Registrar.
     *
     * @param pIdManager the idManager
     */
    public static void register(final GordianKeyPairParserRegistrar pIdManager) {
        final GordianGOSTEncodedParser myParser = new GordianGOSTEncodedParser();
        pIdManager.registerParser(RosstandartObjectIdentifiers.id_tc26_gost_3410_12_256, myParser);
        pIdManager.registerParser(RosstandartObjectIdentifiers.id_tc26_gost_3410_12_512, myParser);
    }

    @Override
    public GordianKeyPairSpec determineKeyPairSpec(final SubjectPublicKeyInfo pInfo) throws GordianException {
        return determineKeyPairSpec(pInfo.getAlgorithm());
    }

    @Override
    public GordianKeyPairSpec determineKeyPairSpec(final PrivateKeyInfo pInfo) throws GordianException {
        return determineKeyPairSpec(pInfo.getPrivateKeyAlgorithm());
    }

    /**
     * Obtain keySpec from Parameters.
     *
     * @param pId the algorithmId
     * @return the keySpec
     * @throws GordianException on error
     */
    private static GordianKeyPairSpec determineKeyPairSpec(final AlgorithmIdentifier pId) throws GordianException {
        /* Determine the curve name */
        final GOST3410PublicKeyAlgParameters myParms = GOST3410PublicKeyAlgParameters.getInstance(pId.getParameters());
        final ASN1ObjectIdentifier myId = myParms.getPublicKeyParamSet();
        final String myName = ECGOST3410NamedCurves.getName(myId);

        /* Determine curve */
        if (myName != null) {
            final GordianCoreGOSTSpec myCurve = GordianCoreGOSTSpec.getCurveForName(myName);
            if (myCurve == null) {
                throw new GordianDataException(GordianECEncodedParser.ERROR_UNSUPCURVE + myName);
            }
            final GordianCoreKeyPairSpecBuilder myBuilder = GordianCoreKeyPairSpecBuilder.newInstance();
            return myBuilder.gost2012(myCurve.getSpec());
        }

        /* Curve is not supported */
        throw new GordianDataException(GordianECEncodedParser.ERROR_UNSUPCURVE + myParms);
    }
}