jdk.crypto.ec/share/classes/sun/security/ec/XDHPrivateKeyImpl.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * particular file as subject to the "Classpath" exception as provided
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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package sun.security.ec;

import java.security.interfaces.XECPrivateKey;
import java.util.Optional;
import java.security.InvalidKeyException;
import java.security.PrivateKey;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.NamedParameterSpec;

import sun.security.pkcs.PKCS8Key;
import sun.security.x509.AlgorithmId;

public final class XDHPrivateKeyImpl extends PKCS8Key implements XECPrivateKey {

    private static final long serialVersionUID = 1L;

    private AlgorithmParameterSpec paramSpec;

    XDHPrivateKeyImpl(XECParameters params, byte[] k)
        throws InvalidKeyException {

        this.paramSpec = new NamedParameterSpec(params.getName());
        this.algid = new AlgorithmId(params.getOid());
        this.key = k.clone();

        checkLength(params);
    }

    XDHPrivateKeyImpl(byte[] encoded) throws InvalidKeyException {

        decode(encoded);
        XECParameters params = XECParameters.get(
            InvalidKeyException::new, algid);
        paramSpec = new NamedParameterSpec(params.getName());

        checkLength(params);
    }

    void checkLength(XECParameters params) throws InvalidKeyException {

        if (params.getBytes() != this.key.length) {
            throw new InvalidKeyException(
                "key length must be " + params.getBytes());
        }
    }

    public byte[] getK() {
        return key.clone();
    }

    @Override
    public String getAlgorithm() {
        return "XDH";
    }

    @Override
    public AlgorithmParameterSpec getParams() {
        return paramSpec;
    }

    @Override
    public Optional<byte[]> getScalar() {
        return Optional.of(getK());
    }
}