org.bouncycastle.tls.TlsECDHKeyExchange Maven / Gradle / Ivy

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The Bouncy Castle Java APIs for the TLS, including a JSSE provider. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified and used appropriately.

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package org.bouncycastle.tls;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.bouncycastle.tls.crypto.TlsCertificate;
import org.bouncycastle.tls.crypto.TlsCertificateRole;
import org.bouncycastle.tls.crypto.TlsSecret;

/**
 * (D)TLS ECDH key exchange (see RFC 4492).
 */
public class TlsECDHKeyExchange
    extends AbstractTlsKeyExchange
{
    private static int checkKeyExchange(int keyExchange)
    {
        switch (keyExchange)
        {
        case KeyExchangeAlgorithm.ECDH_ECDSA:
        case KeyExchangeAlgorithm.ECDH_RSA:
            return keyExchange;
        default:
            throw new IllegalArgumentException("unsupported key exchange algorithm");
        }
    }

    protected TlsCredentialedAgreement agreementCredentials;
    protected TlsCertificate ecdhPeerCertificate;

    public TlsECDHKeyExchange(int keyExchange)
    {
        super(checkKeyExchange(keyExchange));
    }

    public void skipServerCredentials() throws IOException
    {
        throw new TlsFatalAlert(AlertDescription.internal_error);
    }

    public void processServerCredentials(TlsCredentials serverCredentials) throws IOException
    {
        this.agreementCredentials = TlsUtils.requireAgreementCredentials(serverCredentials);
    }

    public void processServerCertificate(Certificate serverCertificate) throws IOException
    {
        this.ecdhPeerCertificate = serverCertificate.getCertificateAt(0).checkUsageInRole(TlsCertificateRole.ECDH);
    }

    public short[] getClientCertificateTypes()
    {
        /*
         * RFC 4492 3. [...] The ECDSA_fixed_ECDH and RSA_fixed_ECDH mechanisms are usable with
         * ECDH_ECDSA and ECDH_RSA. Their use with ECDHE_ECDSA and ECDHE_RSA is prohibited because
         * the use of a long-term ECDH client key would jeopardize the forward secrecy property of
         * these algorithms.
         */
        return new short[]{ ClientCertificateType.ecdsa_fixed_ecdh, ClientCertificateType.rsa_fixed_ecdh };
    }

    public void skipClientCredentials() throws IOException
    {
        throw new TlsFatalAlert(AlertDescription.unexpected_message);
    }

    public void processClientCredentials(TlsCredentials clientCredentials) throws IOException
    {
        this.agreementCredentials = TlsUtils.requireAgreementCredentials(clientCredentials);
    }

    public void generateClientKeyExchange(OutputStream output) throws IOException
    {
        // In this case, the Client Key Exchange message will be sent, but will be empty.
    }

    public void processClientCertificate(Certificate clientCertificate) throws IOException
    {
        this.ecdhPeerCertificate = clientCertificate.getCertificateAt(0).checkUsageInRole(TlsCertificateRole.ECDH);
    }

    public void processClientKeyExchange(InputStream input) throws IOException
    {
        // For ecdsa_fixed_ecdh and rsa_fixed_ecdh, the key arrived in the client certificate
    }

    public boolean requiresCertificateVerify()
    {
        return false;
    }

    public TlsSecret generatePreMasterSecret() throws IOException
    {
        return agreementCredentials.generateAgreement(ecdhPeerCertificate);
    }
}