Lynxtun

---

Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Enformatik Enstitüsü, Bilişim Sistemleri Anabilim Dalı, Türkiye

Tezin Onay Tarihi: 2018

Tezin Dili: Arapça

Öğrenci: GALİP ORAL OKAN

Asıl Danışman (Eş Danışmanlı Tezler İçin): Nazife Baykal

Eş Danışman: Cihangir Tezcan

Özet:

Lynxtun is a VPN solution that allows the creation of a secure tunnel between two hosts over an insecure network. The Lynxtun Protocol transmits fully encrypted datagrams with a fixed size and at a fixed interval using UDP/IP. Our custom authenticated encryption scheme uses the AES-256 block cipher and modified version of GCM mode in order to decrypt and authenticate datagrams efficiently. It ensures traffic flow confidentiality by maintaining a constant bitrate that does not depend on underlying communication. In this sense, it provides unobservable communication. This constitutes a difficult engineering problem. The protocol design allows implementations to fulfill this requirement. We analyze factors that influence realtime behavior and propose solutions to mitigate this. We developed a full implementation for the GNU/Linux operating system in the C programming language. Our implementation succeeds in performing dispatch operations at the correct time, with a tolerance on the order of microseconds, as we have verified empirically.