Google has recently started to give us a Json key file for service account instead of the P12 key file. I have been trying to get this there isn't a lot of information out there and what info I have seen says this should work.
string[] scopes = new string[] { DriveService.Scope.Drive};
Stream stream = new FileStream(jsonKeyFilePath, FileMode.Open, FileAccess.Read, FileShare.Read);
var credential = GoogleCredential.FromStream(stream).CreateScoped(scopes);
However its throwing the following exception
Error creating credential from JSON. Unrecognized credential type .
I have double checked the json key file downloaded two different ones trying to get it to work nothing.