Akademik Veri Yönetim Sistemi
Tezin Türü: Doktora
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Türkiye
Tezin Onay Tarihi: 2003
Tezin Dili: İngilizce
Öğrenci: Kemal Bıçakçı
Danışman: NAZİFE BAYKAL
Özet:Choosing an authentication protocol or a digital signature algorithm becomes more challenging when performance constraints are of concern. In this thesis, we discuss the possible options in a top-down approach and propose viable alternatives for the efficiency criteria. Before all the technical discussions, argue that identifying prerequisites, threats and risks on an organizational conthas utmost importance so that effective solutions can be delivered at a reasonable cost. For instance, one approach to solve the performance problem is to relax the security requirements if it is allowable and use one-time passwords as the more efficient entity authentication protocol. SCOTP is the first protocol proposed in this study which improves the security and flexibility of one-time passwords. After requirements are set up, another high-efficiency solution is based on new designs of improved protocols. These new protocols might utilize the trade-offs between efficiency of distinct system parameters such as communication versus computational load. SAOTS is our new protocol designed to improve the performance and increase the round efficiency of server-assisted signature protocols. With an example in e-health, we also demonstrate that fficiency can be provided on the implementation level as well, the last step in the chain. EVEREST is the third proposal in this thesis which improves the real-time efficiency of digital signatures concerning the fact that the medical images are huge in size and to verify the signature a considerable amount of time is spent to compute the hash of the image file.