Table of Contents

TLS Client

TLS is how the Internet securely works, for banks, airports and security systems. We support TLS 1.3, a global security standard. All encryption, decryption and certification are done in secure internal memory to keep sensitive data safe.

Below is simple example showing how to connect to


Needed NuGets: GHIElectronics.TinyCLR.Devices.Network, GHIElectronics.TinyCLR.Networking.Http

var url = "";

var certificates = Resources.GetBytes(Resources.BinaryResources.GlobalSign);

X509Certificate[] certx509 = new X509Certificate[] { new X509Certificate(certificates) };

int read = 0, total = 0;
byte[] result = new byte[512];

try {
    using (var req = HttpWebRequest.Create(url) as HttpWebRequest){
        req.KeepAlive = false;
        req.HttpsAuthentCerts = certx509;
        req.ReadWriteTimeout = 2000;

        using (var res = req.GetResponse() as HttpWebResponse){
            using (var stream = res.GetResponseStream()){
                do {
                    read = stream.Read(result, 0, result.Length);
                    total += read;

                    System.Diagnostics.Debug.WriteLine("read : " + read);
                    System.Diagnostics.Debug.WriteLine("total : " + total);

                    var page = new String(System.Text.Encoding.UTF8.
                        GetChars(result, 0, read));

                    System.Diagnostics.Debug.WriteLine("Response : " + page);
                while (read != 0);
catch { 


TinyCLR OS uses the internal True Random Number (TRNG) generator to seed the entropy needed. Users can optionally provide their own.

networkInterfaceSetting.TlsEntropy = new byte[] { 0, 1, 2, 3 };

Root Certificate

A root certificate is needed to access secure websites. TinyCLR OS accepts certificates in both text and binary formats. The following instructions show how to download certificates using Google as an example:

First click on the lock icon inside the URL window.

Download Root Certificate Step 1

Select Certificate (Valid) option.

Download Root Certificate Step 2

Select the Certificate Path TAB and click on the top Root certificate, select the Root Certificate

Download Root Certificate Step 3

Next navigate to the Details TAB and click on the Copy to File button.

Download Root Certificate Step 4

The Certificate Export Wizard page will appear, click Next

Download Root Certificate Step 5

Select the Base-64 encoded X.509(.CER) file format and click Next

Download Root Certificate Step 6

Name the file and browse to the location to save. Then click Next

Download Root Certificate Step 7

An export confirmation message will appear, click OK and then click Finish

Download Root Certificate Step 8