c# Sign Xml with X509Certificate2

Question

I try to sign a Xml file. This is the code (from MSDN):

RSACryptoServiceProvider Key = new RSACryptoServiceProvider();
SignXmlFile(XmlStart, XmlEnd, Key);

How can i send as Key a X509Certificate2? Tanks! Francesco

Answer 1

Here you would be using the key (Public / Private Key) from the certificate.

Option 1)

X509Certificate2 cert = RetrieveCertificate("abcd");
var key = cert.PrivateKey;

private static X509Certificate2 RetrieveCertificateFromStore(string certificateName)
{
    X509Store store = new X509Store(StoreName.My, StoreLocation.LocalMachine);
    store.Open(OpenFlags.OpenExistingOnly);
    var cert = store.Certificates.OfType<X509Certificate2>().AsEnumerable().FirstOrDefault(c => c.FriendlyName == certificateName);
    return cert;
}

Or Retrieve Certificate from file:

    private static X509Certificate2 RetrieveCertificateFromFile(string certPath)
    {
        // string certPath = @"C:\Certificates\myCert.pfx";
        string certPass = "mycertPass";
        // Create a collection object and populate it using the PFX file
        X509Certificate2Collection collection = new X509Certificate2Collection();
        collection.Import(certPath, certPass, X509KeyStorageFlags.PersistKeySet);
        // Instead of foreach you can directly retrieve the certificate from collection as well.
        foreach (X509Certificate2 cert in collection)
        {
            // Import the certificates into X509Store objects
            return cert;
        }
        return null;
    }

Option 2)

RSACryptoServiceProvider key = RetrieveKey(cert, EnumKeyType.Private);