public OAuth20ConstructedAssertion ConstructAssertion(string userName) { // Get the UTC Date Timestamp string timestamp = DateTime.UtcNow.ToString("s") + "Z"; // Setup the Assertion String string assertion = String.Format("{0}|{1}|{2}|{3}|{4}|{5}", clientName, publicKey, applicationId, clientString, userName, timestamp); // Generate the CMAC used for Assertion Security string cmac = OAuthUtilities.GenerateCmacHEX(privateKey, assertion); // Add the CMAC to the Assertion String string assertionFinal = String.Format("{0}|{1}", assertion, cmac); return(assertionFinal); }