Would this maybe work?

https://stackoverflow.com/questions/27086117/convert-rsacryptoserviceprovider-rsa-xml-key-to-pkcs8

public static void Convert(string privXmlFilename, string privPkcs8Filename) {
            StringBuilder sb = new StringBuilder ();
            string line;
            var xmlIn = new StreamReader (privXmlFilename);
            while ((line = xmlIn.ReadLine ()) != null) {
                sb.Append (line);
            }
            var xmlKey = sb.ToString ();
            var rsa = RSA.Create ();
            rsa.FromXmlString (xmlKey);
            var bcKeyPair = DotNetUtilities.GetRsaKeyPair(rsa);
            var pkcs8Gen = new Pkcs8Generator (bcKeyPair.Private);
            var pemObj = pkcs8Gen.Generate ();
            var pkcs8Out = new StreamWriter (privPkcs8Filename, false);
            var pemWriter = new PemWriter (pkcs8Out);
            pemWriter.WriteObject (pemObj);
            pkcs8Out.Close ();
        }

Hi, 

Im facing the same issue. I have a privatekey that is not in PEM format (it starts with -----BEGIN PRIVATE KEY-----) and that format does not work in the RSA_PrivateKeyFromPEM action.  When i decrypt the key using this openssl command:

openssl rsa -in privatekey.key -out privatkey.pem -outform PEM

The result is a PEM key that begins with this "-----BEGIN RSA PRIVATE KEY-----" and that is accepted by the RSA_PrivateKeyFromPEM action. 

Is there an action in CryptoAPI I can use to replace this openssl command or does anyone know another forge component that does this? 

regards, Leon

Good day,

I will add another kind request for this feature. We're working on a JWT implementation (via JWT component) that requires the keypair to be in a specific PEM format (PKCS#5/PKCS#8). 

It would be nice if besides converting PEM to XML, it's also possible to translate back from XML to PEM. We hope @João Barata finds the time to implement this action too.

Thanks in advance!