Create an SslSocketFactory using PEM encrypted certificate files

SslUtil.java

/**
 * Utility class to read encrypted PEM files and generate a
 * SSL Socket Factory based on the provided certificates.
 * The original code is by Sharon Asher (link below). I have modified
 * it to use a newer version of the BouncyCastle Library (v1.52)
 * 
 * Reference - https://gist.github.com/sharonbn/4104301"
 */

import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openssl.PEMDecryptorProvider;
import org.bouncycastle.openssl.PEMEncryptedKeyPair;
import org.bouncycastle.openssl.PEMKeyPair;
import org.bouncycastle.openssl.PEMParser;
import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;
import org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder;

import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManagerFactory;
import java.io.FileReader;
import java.security.KeyPair;
import java.security.KeyStore;
import java.security.Security;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;

public class SslUtil {

    public static SSLSocketFactory getSocketFactory(final String caCrtFile, final String crtFile, final String keyFile,
                                                    final String password) {
        try {

            /**
             * Add BouncyCastle as a Security Provider
             */
            Security.addProvider(new BouncyCastleProvider());

            JcaX509CertificateConverter certificateConverter = new JcaX509CertificateConverter().setProvider("BC");

            /**
             * Load Certificate Authority (CA) certificate
             */
            PEMParser reader = new PEMParser(new FileReader(caCrtFile));
            X509CertificateHolder caCertHolder = (X509CertificateHolder) reader.readObject();
            reader.close();

            X509Certificate caCert = certificateConverter.getCertificate(caCertHolder);

            /**
             * Load client certificate
             */
            reader = new PEMParser(new FileReader(crtFile));
            X509CertificateHolder certHolder = (X509CertificateHolder) reader.readObject();
            reader.close();

            X509Certificate cert = certificateConverter.getCertificate(certHolder);

            /**
             * Load client private key
             */
            reader = new PEMParser(new FileReader(keyFile));
            Object keyObject = reader.readObject();
            reader.close();

            PEMDecryptorProvider provider = new JcePEMDecryptorProviderBuilder().build(password.toCharArray());
            JcaPEMKeyConverter keyConverter = new JcaPEMKeyConverter().setProvider("BC");

            KeyPair key;

            if (keyObject instanceof PEMEncryptedKeyPair) {
                key = keyConverter.getKeyPair(((PEMEncryptedKeyPair) keyObject).decryptKeyPair(provider));
            } else {
                key = keyConverter.getKeyPair((PEMKeyPair) keyObject);
            }

            /**
             * CA certificate is used to authenticate server
             */
            KeyStore caKeyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            caKeyStore.load(null, null);
            caKeyStore.setCertificateEntry("ca-certificate", caCert);

            TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(
                    TrustManagerFactory.getDefaultAlgorithm());
            trustManagerFactory.init(caKeyStore);

            /**
             * Client key and certificates are sent to server so it can authenticate the client
             */
            KeyStore clientKeyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            clientKeyStore.load(null, null);
            clientKeyStore.setCertificateEntry("certificate", cert);
            clientKeyStore.setKeyEntry("private-key", key.getPrivate(), password.toCharArray(),
                    new Certificate[]{cert});

            KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(
                    KeyManagerFactory.getDefaultAlgorithm());
            keyManagerFactory.init(clientKeyStore, password.toCharArray());

            /**
             * Create SSL socket factory
             */
            SSLContext context = SSLContext.getInstance("TLSv1.2");
            context.init(keyManagerFactory.getKeyManagers(), trustManagerFactory.getTrustManagers(), null);

            /**
             * Return the newly created socket factory object
             */
            return context.getSocketFactory();

        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }
}

I am getting an error when compiling my Android app. I'm using bcpkix-jdk15on-154.jar and bcprov-ext-jdk15on-154.jar, but Gradle says:
Error:Execution failed for task ':app:transformResourcesWithMergeJavaResForDebug'.

com.android.build.api.transform.TransformException: com.android.builder.packaging.DuplicateFileException:
Duplicate files copied in APK META-INF/BCKEY.SF
File1: D:\dev\src\homeauto\hestia\app\libs\bcpkix-jdk15on-154.jar
File2: D:\dev\src\homeauto\hestia\app\libs\bcprov-ext-jdk15on-154.jar

Should I be including a different set of jars?

Hi @weswitt I was having the same error. For me it seems like I had redundant or repeated libraries, meaning jar files. The fact is that after finding out that bouncycastle was not complete for Android, ended up using spongycastle and then at some poing I had libraries from both castles in the project, that caused a mess, but once I was rid of all extra libraries I was not using it all compiled properly.

@weswitt that is because 'bcprov-ext-jdk15on-154.jar' includes the other jar, so there is no need to include both. Just include the extensions jar.

@nyyrikki have you generated all the certificates properly ?

Hi @rohanag12 I would like to connect to MQTT broker with TLSv1.2 authenticated by Pre-Shared Key standard (RFC 4279). How do I change the code example to apply it ?

@weswitt for android, maybe you need to try to use spongy castle.

I'm not sure why I'm getting this error, maybe the client certificate is not generated properly.

org.eclipse.paho.android.service.MqttTokenAndroid@2a7465ed 04-26 12:50:29.703 18206-18206/.service.TraccarService E/PahoConnector: Throwable: MqttException (0) - javax.net.ssl.SSLException: Error setting private key: ssl=0xb7ad3d60: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch (external/openssl/crypto/x509/x509_cmp.c:330 0xae758005:0x00000000)

What is the license or governance of this? sharonbn's original gist doesn't have any licensing information either.

@weswitt did you resolved that error?

Hello Guyz, I am connecting to server using server CA, Client CA & Private key, where all three are .pem files. But for private key there is no password, so am using random password. After connecting to server at handshake I am getting error like : fatal error Handshake failure.

WRITE: TLSv1.2 Handshake, length = 40
SwingWorker-pool-1-thread-1, READ: TLSv1.2 Alert, length = 2
SwingWorker-pool-1-thread-1, RECV TLSv1.2 ALERT: fatal, handshake_failure
%% Invalidated: [Session-1, TLS_DHE_RSA_WITH_AES_256_GCM_SHA384]
SwingWorker-pool-1-thread-1, called closeSocket()
SwingWorker-pool-1-thread-1, handling exception: javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure

Can any one guide please?

I have added support for server hostname ignore in the following updated code. Also it works with latest BouncyCastle version 1.68.

This will also support for client and server certificate verification as well only server certificate for clients who doesn't have client certs but only have rootCA using which server certs were signed.

https://gist.github.com/saumilsdk/1e17e30e33d0a18f44ce4e2b5841b281