http://hdl.handle.net/20.500.12416/2 2026-10-28T16:04:04Z 2026-10-28T16:04:04Z Abdulkareem, Marwa Issam Ashour, Osama Ibraheem Salman, Yücel Batu http://hdl.handle.net/20.500.12416/8516 2024-10-23T07:22:25Z 2023-01-01T00:00:00Z

Secure IoT Entrance Using Mobile Application Abdulkareem, Marwa Issam; Ashour, Osama Ibraheem; Salman, Yücel Batu The impact of cyber security attacks increased globally, implementing proper security standards to protect data in the cyber environment has been prioritized, while assets are also at risk of being exploited through physical security breaches. Considering the potential risk of Radio Frequency Identification (RFID) cards being lost or stolen, third parties can effortlessly gain the privileges of an authorized person. In this paper, we propose a design for a secure access control system that operates on an Android phone with multi-factor authentication to enable secure access control systems. For this purpose, the authorized users are registered in a database that can be accessed by the access control system when the user authenticates his\her credentials with a login/password as well as biometric data from his\her smartphone. This system works when the user is 10 meters away from the access control system, after that the user will be asked to submit his\her biometric credentials. The database then compares the user's keys and grants access if authentication is successful. This design is intended to reduce the number of cases in which unauthorized access to a restricted area. The observed results clearly meet the required security of physical access control systems.

2023-01-01T00:00:00Z Saran, Ayse Nurdan http://hdl.handle.net/20.500.12416/8503 2024-07-04T10:05:31Z 2024-01-01T00:00:00Z

On time-memory trade-offs for password hashing schemes Saran, Ayse Nurdan A password hashing algorithm is a cryptographic method that transforms passwords into a secure and irreversible format. It is used not only for authentication purposes but also for key derivation mechanisms. The primary purpose of password hashing is to enhance the security of user credentials by preventing the exposure of plaintext passwords in the event of a data breach. As a key derivation function, password hashing aims to derive secret keys from a master key, password, or passphrase using a pseudorandom function. This review focuses on the design and analysis of time-memory trade-off (TMTO) attacks on recent password hashing algorithms. This review presents a comprehensive survey of TMTO attacks and recent studies on password hashing for authentication by examining the literature. The study provides valuable insights and strategies for safely navigating transitions, emphasizing the importance of a systematic approach and thorough testing to mitigate risk. The purpose of this paper is to provide guidance to developers and administrators on how to update cryptographic practices in response to evolving security standards and threats.

2024-01-01T00:00:00Z Arslan, Caner Karasakal, Orhan Kırca, Ömer http://hdl.handle.net/20.500.12416/8488 2024-06-12T12:04:17Z 2024-01-01T00:00:00Z

Naval Air Defense Planning problem: A novel formulation and heuristics Arslan, Caner; Karasakal, Orhan; Kırca, Ömer This article focuses on air defense in maritime environment, which involves protecting friendly naval assets from aerial threats. Specifically, we define and address the Naval Air Defense Planning (NADP) problem, which consists of maneuvering decisions of the ships and scheduling weapons and sensors to the threats in order to maximize the total expected survival probability of friendly units. The NADP problem is more realistic and applicable than previous studies, as it considers features such as sensor assignment requirements, weapon and sensor blind sectors, sequence-dependent setup times, and ship's infrared/radar signature. In this study, a mixed-integer nonlinear programming model of the NADP problem is presented and heuristic solution approaches are developed. Computational results demonstrate that these heuristic approaches are both fast and efficient in solving the NADP problem.

2024-01-01T00:00:00Z Gökçe, Muhsin Caner Baykal, Yahya Ata, Yalçın Gerçekcioğlu, Hamza http://hdl.handle.net/20.500.12416/8487 2024-06-05T11:43:48Z 2024-02-01T00:00:00Z

Multimode beam propagation through atmospheric turbulence Gökçe, Muhsin Caner; Baykal, Yahya; Ata, Yalçın; Gerçekcioğlu, Hamza The investigation focuses on studying the propagation characteristics of multimode lasers in the turbulent amosphere. By employing the Huygens-Fresnel integral, we develop analytical formulations for various propagation parameters. These include the average intensity distribution, kurtosis parameter, beam spread, and the average transmittance of multimode beams in turbulent atmosphere. Our findings reveal that as the propagation distance or the structure constant of the atmosphere increases, i.e., turbulence becomes stronger, the kurtosis parameter and the beam spread increase. The multimode beam exhibits a Gaussian like intensity profile when the propagation distance is significantly increased or when the structure constant becomes sufficiently large. For the case of the Gaussian beam, the kurtosis parameter is found to be 3. The multimode beam's kurtosis parameter rises as the turbulence becomes stronger and eventually approaches 3. Raising the mode content leads to a rise in the average transmittance; however, it leads to a decline in the Kurtosis parameter and the beam spread.

2024-02-01T00:00:00Z