Authenticate a user using web service in windows 8

Question

I am trying to authenticate a user in windows 8. After authentication there will be many CRUD calls that can be called. There are services to perform these CRUD operations. To prevent unauthorized calls to these CRUD services, I pass an additional parameter GUID(Hashed) returned after a successful login and passed to these services on each call, I store this GUID and the username in the database. This is my model to authenticate and to perform CRUD operations. Do you think its doable and secure? Or are there other better methods?

Answer 1

it depends. Remember that everyone can catch your GUID using simple Wireshark. If you're sure that you're GUID is safe and undecodeble that sure. Your way will be fine, but if now you know the answer