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Validate LTI TOKEN

Question asked by jbermejo on Feb 27, 2018
Latest reply on Mar 19, 2018 by vickers.stephen



May be someone can help me.

I have a LTI token from a blackboard site and C#, I have the secret and all inputs. But I can´t validate it.

I'm using OAuthUtility CodePlex Archive downloaded from Nuget.


request.HttpMethod is POST


string signatureBase = OAuthUtility.GenerateSignatureBase(request.HttpMethod, request.Url, parameters);

string signature = getSignature(signatureBase, consumerSecret);


    private string getSignature(string message, string secret)


            UTF8Encoding encoding2 = new UTF8Encoding();

            byte[] secretKey = encoding2.GetBytes(secret);

            byte[] counter = encoding2.GetBytes(message);

            var hmacsha1 = new HMACSHA1(secretKey);

            byte[] hmac_result = hmacsha1.ComputeHash(counter);

            return Convert.ToBase64String(hmac_result);



I tryed putting in the screct '&' Do I need a secret Token /secret&sectedToken)?

and I have some imputs like ext_launch_presentation_css_url  (ext_) that I don´t know if I have to put in the SignatureBase.