How do I do TLS with BouncyCastle?

Question

Does anybody know about examples of TLS with BouncyCastle? I was surprised by the lack of them on Internet. If there are really none, let's collect them as answers.

Answer 1

One more example, built on top of the server-only auth answer: TLS with self-signed certs with client authentication (I am showing just the changed parts). This is the server part:

tlsServerProtocol.accept(new DefaultTlsServer() {
    protected TlsSignerCredentials getRSASignerCredentials() throws IOException {
        return tlsSignerCredentials(context);
    }
    public void notifyClientCertificate(Certificate clientCertificate) throws IOException {
        validateCertificate(clientCertificate);
    }
    public CertificateRequest getCertificateRequest() {
        return new CertificateRequest(new short[] { ClientCertificateType.rsa_sign },  new Vector<Object>());
    }
});        

And this is the client part:

tlsClientProtocol.connect(new DefaultTlsClient() {            
    public TlsAuthentication getAuthentication() throws IOException {
        return new TlsAuthentication() {                    
            public void notifyServerCertificate(Certificate serverCertificate) throws IOException {
                validateCertificate(serverCertificate);
            }
            public TlsCredentials getClientCredentials(CertificateRequest certificateRequest) throws IOException {
                return tlsSignerCredentials(context);
            }
        };
    }
});

Answer 2

Scenario: Our production server is using JDK1.6. However customer server is upgraded to only communicate in TLS 1.2. SSL Communication between both servers is broken. But we cannot simply upgrade JDK6 to 8 (which is supporting TLS 1.2 by default) because this will cause other libraries compatibility issue.

The following sample code uses jdk1.6.0_45 and bcprov-jdk15on-153.jar (Bouncy Castle SIGNED JAR FILES) to connect to any server using TLS.

import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.Socket;

import org.bouncycastle.crypto.tls.CertificateRequest;
import org.bouncycastle.crypto.tls.DefaultTlsClient;
import org.bouncycastle.crypto.tls.TlsAuthentication;
import org.bouncycastle.crypto.tls.TlsClientProtocol;
import org.bouncycastle.crypto.tls.TlsCredentials;

public class TestHttpClient {
    // Reference: http://boredwookie.net/index.php/blog/how-to-use-bouncy-castle-lightweight-api-s-tlsclient/
    //            bcprov-jdk15on-153.tar\src\org\bouncycastle\crypto\tls\test\TlsClientTest.java
    public static void main(String[] args) throws Exception {
        java.security.SecureRandom secureRandom = new java.security.SecureRandom();
        Socket socket = new Socket(java.net.InetAddress.getByName("www.google.com"), 443);
        TlsClientProtocol protocol = new TlsClientProtocol(socket.getInputStream(), socket.getOutputStream(),secureRandom);
        DefaultTlsClient client = new DefaultTlsClient() {
            public TlsAuthentication getAuthentication() throws IOException {
                TlsAuthentication auth = new TlsAuthentication() {
                    // Capture the server certificate information!
                    public void notifyServerCertificate(org.bouncycastle.crypto.tls.Certificate serverCertificate) throws IOException {
                    }

                    public TlsCredentials getClientCredentials(CertificateRequest certificateRequest) throws IOException {
                        return null;
                    }
                };
                return auth;
            }
        };
        protocol.connect(client);

        java.io.OutputStream output = protocol.getOutputStream();
        output.write("GET / HTTP/1.1\r\n".getBytes("UTF-8"));
        output.write("Host: www.google.com\r\n".getBytes("UTF-8"));
        output.write("Connection: close\r\n".getBytes("UTF-8")); // So the server will close socket immediately.
        output.write("\r\n".getBytes("UTF-8")); // HTTP1.1 requirement: last line must be empty line.
        output.flush();

        java.io.InputStream input = protocol.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(input));
        String line;
        while ((line = reader.readLine()) != null)
        {
            System.out.println(line);
        }
    }
}

Sample output shows that JDK 6 can obtain the server page in TLS, rather than some SSL Exception:

HTTP/1.1 302 Found
Cache-Control: private
Content-Type: text/html; charset=UTF-8
Location: https://www.google.com.sg/?gfe_rd=cr&ei=WRgeVovGEOTH8Afcx4XYAw
Content-Length: 263
Date: Wed, 14 Oct 2015 08:54:49 GMT
Server: GFE/2.0
Alternate-Protocol: 443:quic,p=1
Alt-Svc: quic="www.google.com:443"; p="1"; ma=600,quic=":443"; p="1"; ma=600
Connection: close

<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="https://www.google.com.sg/?gfe_rd=cr&amp;ei=WRgeVovGEOTH8Afcx4XYAw">here</A>.
</BODY></HTML>

Answer 3

This is a very basic example, with server-only authentication and self-signed cert. The code is based on BC 1.49, mostly leightweight API:

ServerSocket serverSocket = new ServerSocket(SERVER_PORT);
final KeyPair keyPair = ...
final Certificate bcCert = new Certificate(new org.spongycastle.asn1.x509.Certificate[] {
    new X509V3CertificateStrategy().selfSignedCertificateHolder(keyPair).toASN1Structure()}); 
while (true) {
    Socket socket = serverSocket.accept();
    TlsServerProtocol tlsServerProtocol = new TlsServerProtocol(
    socket.getInputStream(), socket.getOutputStream(), secureRandom);
    tlsServerProtocol.accept(new DefaultTlsServer() {
        protected TlsSignerCredentials getRSASignerCredentials() throws IOException {
            return tlsSignerCredentials(context);
        }               
    });      
    new PrintStream(tlsServerProtocol.getOutputStream()).println("Hello TLS");
}

where

private TlsSignerCredentials tlsSignerCredentials(TlsContext context) throws IOException {
    return new DefaultTlsSignerCredentials(context, bcCert,
            PrivateKeyFactory.createKey(keyPair.getPrivate().getEncoded()));                
}

This is the client code:

Socket socket = new Socket(<server IP>, SERVER_PORT);
TlsClientProtocol tlsClientProtocol = new TlsClientProtocol(    
    socket.getInputStream(), socket.getOutputStream());
tlsClientProtocol.connect(new DefaultTlsClient() {          
    public TlsAuthentication getAuthentication() throws IOException {
        return new ServerOnlyTlsAuthentication() {                  
            public void notifyServerCertificate(Certificate serverCertificate) throws IOException {
                validateCertificate(serverCertificate);
            }
        };
    }
});
String message = new BufferedReader(
    new InputStreamReader(tlsClientProtocol.getInputStream())).readLine();

You need to use the input and output stream from tlsClient/ServerProtocol to read and write encrypted data (e.g. tlsClientProtocol.getInputStream()). Otherwise, if you used e.g. socket.getOutputStream(), you would just write unencrypted data.

How to implement validateCertificate? I am using self-signed certificates. This means I just look them up in the key-store without any certificate chains. This is how I create the key store:

KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
keyStore.load(null, password);
X509Certificate certificate = ...;
keyStore.setCertificateEntry(alias, certificate);

And this is the validation:

private void validateCertificate(org.spongycastle.crypto.tls.Certificate cert) throws IOException, CertificateException, KeyStoreException {
    byte[] encoded = cert.getCertificateList()[0].getEncoded();
    java.security.cert.Certificate jsCert = 
        CertificateFactory.getInstance("X.509").generateCertificate(new ByteArrayInputStream(encoded));
    String alias = keyStore.getCertificateAlias(jsCert);
    if(alias == null) {
        throw new IllegalArgumentException("Unknown cert " + jsCert);
    }
}

What is rather confusing, are the three different Certificate classes. You have to convert between them as shown above.