Abstract:  In public competitions or university exams, candidates have to trust the examiner to mark fairly. The same requirement also applies when the competition adopts the known double envelope method. To rebalance that trust, candidate authentication should be achieved together with anonymity during the marking. WATA achieves this contradictory combination in various forms since its first release. Additional requirements are auditability, verifiability and usability. In particular, to meet the last, the system should be managed remotely. The current version, WATA3, meets some of these requirements, but is also found to suffer some serious weaknesses. Thus, a novel version, WATA4, is advanced to achieve all of the desired requirements.