org.bouncycastle.tls.crypto.impl.jcajce.JceX25519Domain 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.crypto.impl.jcajce;

import java.io.IOException;
import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;

import org.bouncycastle.asn1.ASN1Encoding;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.tls.AlertDescription;
import org.bouncycastle.tls.TlsFatalAlert;
import org.bouncycastle.tls.crypto.TlsAgreement;
import org.bouncycastle.tls.crypto.TlsCryptoException;
import org.bouncycastle.tls.crypto.TlsECDomain;

public class JceX25519Domain implements TlsECDomain
{
    protected final JcaTlsCrypto crypto;

    public JceX25519Domain(JcaTlsCrypto crypto)
    {
        this.crypto = crypto;
    }

    public JceTlsSecret calculateECDHAgreement(PrivateKey privateKey, PublicKey publicKey)
        throws IOException
    {
        try
        {
            byte[] secret = crypto.calculateKeyAgreement("X25519", privateKey, publicKey, "TlsPremasterSecret");

            if (secret == null || secret.length != 32)
            {
                throw new TlsCryptoException("invalid secret calculated");
            }
            if (TlsArrays.areAllZeroes(secret, 0, secret.length))
            {
                throw new TlsFatalAlert(AlertDescription.handshake_failure);
            }

            return crypto.adoptLocalSecret(secret);
        }
        catch (GeneralSecurityException e)
        {
            throw new TlsCryptoException("cannot calculate secret", e);
        }
    }

    public TlsAgreement createECDH()
    {
        return new JceX25519(this);
    }

    public PublicKey decodePublicKey(byte[] encoding) throws IOException
    {
        try
        {
            AlgorithmIdentifier algID = new AlgorithmIdentifier(EdECObjectIdentifiers.id_X25519);
            SubjectPublicKeyInfo spki = new SubjectPublicKeyInfo(algID, encoding);
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(spki.getEncoded(ASN1Encoding.DER));

            KeyFactory kf = crypto.getHelper().createKeyFactory("X25519");
            return kf.generatePublic(keySpec);
        }
        catch (Exception e)
        {
            throw new TlsFatalAlert(AlertDescription.illegal_parameter, e);
        }
    }

    public byte[] encodePublicKey(PublicKey publicKey) throws IOException
    {
        try
        {
            if ("X.509".equals(publicKey.getFormat()))
            {
                SubjectPublicKeyInfo spki = SubjectPublicKeyInfo.getInstance(publicKey.getEncoded());
                return spki.getPublicKeyData().getOctets();
            }
        }
        catch (Exception e)
        {
        }

        throw new TlsFatalAlert(AlertDescription.internal_error);
    }

    public KeyPair generateKeyPair()
    {
        try
        {
            KeyPairGenerator keyPairGenerator = crypto.getHelper().createKeyPairGenerator("X25519");
            keyPairGenerator.initialize(255, crypto.getSecureRandom());
            return keyPairGenerator.generateKeyPair();
        }
        catch (GeneralSecurityException e)
        {
            throw Exceptions.illegalStateException("unable to create key pair: " + e.getMessage(), e);
        }
    }
}