Loading Root Certificate on Compact Framework .NET - compact-framework

Question

I am trying to load an x509 certificate from file in CF.NET. The certificate I am trying to load can be downloaded here (it's a GoDaddy root cert).
My code looks like this:
byte[] bytes = null;
using (var certFile = new FileStream("\\gdroot-g2.crt", FileMode.Open, FileAccess.Read))
using (var br = new BinaryReader(certFile))
{
bytes = new byte[(int)certFile.Length];
br.Read(bytes, 0, bytes.Length);
}
//This line throws the error.
var cert = new X509Certificate2(bytes);
When I try loading the cert, I get the following error:
Creating certificate object failed. The data passed in is either
incorrect or is not supported by .NET Compact Framework. .NET Compact
Framework does not support reading from pfx files.
I've verified that the .CRT file I am using is Base-64 encoded. Also - when I run this same code on the desktop (using a mobile simulator that we've built) it parses the cert successfully.
Am I missing something basic here?

Answer 1

I too had the same problem and I resolved it by following the below steps.
Convert the certificate file to DER encoded binary X.509 format and then use it in the compact framework.
Steps for conversion:
Open the .cer file in the computer
Go to "Details" tab and click "Copy to File..." button
Certificate Export Wizard appears in which click Next and choose "DER encoded binary X.509(.CER)"
Click Next and specify the desired location and file name and click Finish
This will generate a .cer file in the chosen location
Use the certificate file (generated by the above process) in the compact framework and access the information programmatically as follows.
Read the contents of certificate file using BinaryReader which results in byte[] value
X509Certificate2 cert = new X509Certificate2(byte value returned by the above step)
Get the issuer name or any details required through built-in methods like cert.GetIssuerName();
When I followed this procedure, I didn't get any exception and it worked fine.

Answer 2

You might find it easier to interact with the certificate via the X509Store class. You can either add the root certificate by hand or programmatically.
Once you've added your certificate to the store you can retrieve an enumeration of the X509Certificate2 from the store and use LINQ to filter down to the specific GoDaddy certificate.
The linked MSDN page has some sample code showing this in action. Hope this helps.

Answer 3

The X509 namespace in the CF is effectively useless. I'm not sure why they bothered including it at all. I ended up wrapping the certificate APIs manually and creating a separate set of X509 classes that provide the functionality the BCL should have provided. The code is too long for a post here on SO, but those methods are part of the SDF.