Yazar "Aytaş, Nilay" seçeneğine göre listele
Listeleniyor 1 - 8 / 8
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A Novel Identity-Based Privacy-Preserving Anonymous Authentication Scheme for Vehicle- to-Vehicle Communication(Kaunas Univ Technology, 2023) Genç, Yasin; Korkuç, Çağatay; Aytaş, Nilay; Afacan, Erkan; Sazlı, Murat H.; Yazgan, ErdemThis paper proposes a novel bilinear pairing-free identity-based privacy-preserving anonymous authentication scheme for vehicle-to-vehicle (V2V) communication, called NIBPA. Today, vehicular ad hoc networks (VANETs) offer important solutions for traffic safety and efficiency. However, VANETs are vulnerable to cyberattacks due to their use of wireless communication. Therefore, authentication schemes are used to solve security and privacy issues in VANETs. The NIBPA satisfies the security and privacy requirements and is robust to cyberattacks. It is also a pairing-free elliptic curve cryptography (ECC)-based lightweight authentication scheme. The bilinear pairing operation and the map-to-point hash function in cryptography have not been used because of their high computational costs. Moreover, it provides batch message verification to improve VANETs performance. The NIBPA is compared to existing schemes in terms of computational cost and communication cost. It is also a test for security in the random oracle model (ROM). As a result of security and performance analysis, NIBPA gives better results compared to existing schemes.Öğe Bir anten dizisine gelen sinyalin yönünün tekil değer ayrışımı ve matris kalem yöntemi ile bulunması(Kırıkkale Üniversitesi, 2017) Aytaş, Nilay; Tuna, Eyüp; Afacan, ErkanSinyal kaynaklarının yönünün tespiti, radar sistemleri, konum bulma sistemleri, elektronik harp sistemleri gibi askeri sistemler başta olmak üzere maden rezervlerinin tespiti, mobil iletişim sistemleri, kaçak radyo yayınlarının bulunması, kaybolan dağcıların yerinin tespiti gibi sivil uygulamalarda da etkin bir şekilde kullanılmaktadır. İlk dönemlerde sadece tek bir sinyal kaynağının konumunu belirleyen sistemler günümüzde alt uzay tekniklerinin gelişmesi ile aynı anda birçok sinyal kaynağından gelen sinyallerin yönünü ve konumunu tespit edebilme yeteneğini kazanmıştır. Tekil Değer Ayrışımı yöntemi ile Matris Kalem yöntemi sinyalin alt uzay analizinde kullanılan yöntemlerden ikisidir. Bu çalışmada söz konusu iki yöntemi kullanarak anten dizisine bir veya birden fazla sinyal kaynağından gelen sinyallerin geliş yönlerinin belirlenmesi amaçlanmıştır. Ayrıca anten dizisine gelen sinyallerin gürültü içerip içermemesi durumu da göz önünde bulundurularak sonuçlar karşılaştırılmıştır. Elde edilen sonuçlar Tekil Değer Ayrışımı ve Matris Kalem yöntemi ile anten dizisine gelen sinyallerin yönünün belirlendiğini, sinyal kaynağı sayısı ile sisteme ait tekil değerler arasında doğru orantı olduğunu ve sinyal gürültü oranı ile tekil değerler arasında ise ters orantı olduğunu göstermiştir.Öğe Digital Image Encryption Using Elliptic Curve Cryptography: A Review(Institute of Electrical and Electronics Engineers Inc., 2022) Habek, Muhammed; Genç, Yasin; Aytaş, Nilay; Akkoç, Ahmet; Afacan, Erkan; Yazgan, ErdemToday, digital images are used in many different applications. They can be social media applications or critical applications such as military and medical. However, cyber attacks or privacy problems also cause serious security problems for digital images. Therefore, various methods are proposed to ensure privacy and security. The first science that comes to mind is cryptography. It is a science of encryption. Encryption methods ensure the privacy of data. Many encryption methods are used to ensure the privacy and accuracy of the digital images. This paper reviews the encryption method based on elliptic curve cryptography for digital image encryption. This review describes the parameters and security attacks that affect the performance of digital image encryption. In addition, existing studies are reviewed. Thus, this paper is about the usefulness of both design criteria to be considered for new digital image encryption methods and comparing existing studies. © 2022 IEEE.Öğe ELCPAS: A new efficient lightweight certificateless conditional privacy preserving authentication scheme for IoV(Elsevier, 2023) Genç, Yasin; Aytaş, Nilay; Akkoç, Ahmet; Afacan, Erkan; Yazgan, ErdemThis paper proposes a new efficient certificateless conditional privacy preserving authentication (CL-CPPA) scheme named ELCPAS, which is pairing-free, energy-efficient, lightweight which uses elliptic curve cryptography (ECC) for internet of vehicles (IoV). The ELCPAS is based on the certificateless signature scheme that eliminates the key escrow problem, which is the drawback of identity-based encryption. It performs batch message verification with a very efficient method which minimizes the delays in the message verification phase. In our proposed scheme, users (vehicle etc.) do not need to communicate with central units during each message signing. Thus, the computational load and connection problems in the central units are minimized. It is also quite fast as it does not use the bilinear pairing and map-to-point operations. The performance evaluation shows that ELCPAS has efficiency in scope of computation cost, communication cost and energy consumption cost compared to other existing schemes. The security evaluation is performed according to the random oracle model (ROM) and the proposed ELCPAS scheme has been shown to be secure. In addition, it provides security requirements and it is resistant to cyber-attacks. The results of the analyses performed according to the security criteria show that it is secure.(c) 2022 Elsevier Inc. All rights reserved.Öğe Elliptic Curve Cryptography for Security in Connected Vehicles(IEEE, 2022) Genç, Yasin; Habek, Muhammed; Aytaş, Nilay; Akkoç, Ahmet; Afacan, Erkan; Yazgan, ErdemThe concept of a connected vehicle refers to the linking of vehicles to each other and to other things. Today, developments in the Internet of Things (IoT) and 5G have made a significant contribution to connected vehicle technology. In addition to many positive contributions, connected vehicle technology also brings with it many security-related problems. In this study, a digital signature algorithm based on elliptic curve cryptography is proposed to verify the message and identity sent to the vehicles. In the proposed model, with the anonymous identification given to the vehicle by the central unit, the vehicle is prevented from being detected by other vehicles and third parties. Thus, even if the personal data produced in the vehicles is shared, it cannot be found which vehicle it belongs to.Öğe Signal and Noise Subspace Decomposition for a Linear Antenna Array Using SVD(Ieee, 2018) Aytaş, Nilay; Afacan, Erkan; İnanç, NihatIn the vast majority of signal processing applications, the signal is intended to be analyzed to obtain a variety of data from the signal. It is decomposed into signal subspaces to perform this analysis. The noise in the signal during analysis is undesirable. If the signal incoming to an antenna array contains noise, it should be filtered before processing signal. In this study, we have tried to divide the uniform linear antenna array into subspaces of incoming signals from multiple signal sources with various frequencies, noise and arrival angles. The Singular Value Decomposition (SVD) method is used to separate the signal subspace and noise subspace. According to the singular values obtained, the information about the frequencies of the signals and whether the signal contains noise. Also, the number of sources can be estimated by means of singular values.Öğe The Application of Matrix Pencil Method for Direction Finding Using a Linear Antenna Array(IEEE, 2021) Aytaş, Nilay; Afacan, Erkan; İnanç, NihatThe estimation of the direction of signal sources is used especially in military applications such as radar systems, locating systems, military warfare systems, and in civil applications such as mobile communication systems. The systems that used to only determine the location of a single signal source have obtained the ability to simultaneously detect the direction and location of signals from multiple signal sources following the development of subspace techniques. Matrix Pencil method is a method used in subspace analysis of the signal, in this study, it is aimed to estimate the direction of arrival of the signals impinging from one or more signal sources to the antenna array using this method. The analysis showed that high accuracy results have been obtained in the estimation of the direction of arrival the signals impinging to the antenna array by Matrix Pencil method.Öğe Zaman modülasyonlu doğrusal anten dizilerinin matris kalem yöntemi ile incelenmesi(Kırıkkale Üniversitesi, 2022) Aytaş, Nilay; İnanç, Nihat; Afacan, ErkanBu tez çalışmasının amacı; önerilen yeni bir yaklaşımla, zaman modülasyonlu doğrusal anten dizisi ile sinyal geliş açısının analizler yapılarak tahmin edilmesidir. Matris Kalem yönteminin zaman modülasyonlu doğrusal anten dizisiyle birleştirilmesi sayesinde, tek anlık görüntü kullanılması ile büyük bir veri avantajı elde edilmiştir. Bu tez çalışmasında, zaman modülasyonu ile Matris Kalem yöntemlerini birleştiren yeni bir formülasyon geliştirilmiştir. Sinyal geliş açısı tahmini için zaman adımları, Diferansiyel Evrim Algoritması kullanılarak optimize edilmiştir. Gürültü seviyesi, sinyal kaynağı sayısı, anten elemanı sayısı ve farklı sinyal geliş açılarının etkileri, simülasyonlar ile incelenmiş ve karşılaştırmalar sunulmuştur. Simülasyon sonuçları; önerilen yeni yaklaşımın, geleneksel yön tahmini yöntemleriyle karşılaştırıldığında, özellikle tek anlık görüntü sayısına ve yüksek gürültü seviyelerine sahip senaryolar için tahmin doğruluğu açısından önemli avantajlar sağladığını göstermektedir.
