Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Privacy-Preserving Rare Disease Analysis With Fully Homomorphic Encryption(01. Izmir Institute of Technology, 2023) Akkaya, Güliz; Erdoğmuş, Nesli; Akgün, MeteRare diseases severely affect many people across the world at the present time. Researchers conduct studies to understand the reasons behind rare diseases and as a result of this research, diagnosis, and treatment methods are developed. Rare disease analysis is performed to specify the disease-causing variants on the genome data of patients. The researchers need access to as much genome data as possible to find causing variants of rare diseases. On the other hand, the genome data of patients should be protected because it can be used to detect the identity of individuals. The researchers are not able to share the genome data of patients easily because of regulations such as General Data Protection Regulation (GDPR). For this reason, rare disease analysis should be performed in a secure way that protects the privacy of patients while enabling the collaboration of multiple medical institutions. In this context, a privacy-preserving collaborative system for rare disease analysis should be provided. This thesis study focuses on the utilization of fully homomorphic encryption, a method that enables unlimited number of operations to be performed on encrypted data, for privacy-preserving collaborative rare disease analysis. Two different methods, the boolean circuit method, and the integer arithmetic method, are implemented to perform rare disease analysis on the encrypted genome data to find disease-causing variants, and various experiments are performed to assess the efficiency of the proposed methods.Master Thesis P/Key: Puf Based Second Factor Authentication(01. Izmir Institute of Technology, 2022) Uysal, Ertan; Akgün, Mete; Şahin, SerapSecond-factor authentication mechanisms increase the security of authentication processes by implementing an additional auxiliary layer to a single factor. As a second factor, using one-time passwords (OTP) is mainly preferred due to their hardware independence and easy generation. OTP generation protocols should be evaluated in two main categories: time and security. In time-based OTP mechanisms (TOTP), client and server store a shared secret key. However, if attackers compromise the server, attackers can generate new OTPs using the key and impersonate the client. To solve this problem, protocols based on the hash chain mechanism have been proposed; however, these methods have weaknesses mainly due to the authentication speed and the limited number of OTPs they generate. This thesis proposes a server-side tamper-proof and fast response physical unclonable function (PUF) based second-factor authentication protocol on overcoming these problems. PUF is a digital fingerprint that ensures that every device produced is unique due to uncontrollable factors in the production stages of devices. It generates responses that correspond to challenges. Since PUF is based on the micro-level differences in devices, micro-level structure changes in the event of an attack, and the PUF takes to generate different responses. Although PUF is a fast response function, it is impossible to reach the challenge from the response it generates. In the proposed protocol, the PUF inside the server generates key values and used to store clients’ secret seed values securely. In case of side-channel attack on server-side, the key values of the clients cannot be obtained by the attackers, as the PUF structure will be corrupted. Even if the attacker obtains the server’s credentials and gains access to the system, they cannot get the secret seed values of the clients and cannot generate the OTPs. In this way, the attacker cannot authenticate by impersonating the client.