Digital signature apply to http request body

 public CheckValiedContent (HttpRequest request){

          string xeroPrivateKey = Environment.GetEnvironmentVariable("XEROKEY");

          var signatureHeader = request.Headers["x-xero-signature"];

          var requestBody = request.Body;

         var resultSignature = GenarateSignature(requestBody,xeroPrivateKey);

         if (signatureHeader != resultSignature){

            return 401

        }

 }

 public string GenerateSignature(string dataToHash, string xeroKey)
        {
            using (var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(xeroKey)))
            {
                var messageBytes = Encoding.UTF8.GetBytes(dataToHash);
                var hash = hmac.ComputeHash(messageBytes);
                return Convert.ToBase64String(hash);
            }
        }