Hakan Kilinc

• PhD
• PhD at Gebze Technical University

We present a survey of authentication and key agreement schemes that are proposed for the SIP protocol. SIP has become the center piece for most VoIP architectures. Performance and security of the authentication and key agreement schemes are two critical factors that affect the VoIP applications with large number of users. Therefore, we have identi...

In a widely deployed VoIP system tens of thousands of clients compete for the SIP proxy server's authentication service. SIP protocol implementations have to meet certain QoS and security requirements. In this study new ID-based protocols are proposed for the SIP authentication and key agreement protocols. These protocols minimize the use of expens...

VoIP services have become a major competitor to the PSTN networks and will replace them in the near future. Based on this fact the SIP protocol became very popular. But handling tens of thousand of clients, despite the network and application delays is a challenging task. The SIP proxy servers need to be implemented very efficiently to reduce the a...

Dealing with malicious nodes is an important issue for many types of overlay networks. In overlay networks, malicious nodes can drop, delay or in other ways subvert user traffic, modify packets and break protocols required for the successful operation of the system. We propose a reputation management model supported by an ID based cryptosystem to r...

The SIP authentication mechanism implemented in most applications is the HTTP Digest Authentication. This mechanism is easy to implement and delivers high performance results. But the weaknesses of this authentication method are not acceptable where security is of high concern. The ID based authentication mechanisms do not suffer from the vulnerabi...

The recent attacks initiated by malware-infected IoT devices illustrate that these attacks have tremendous impacts not only on the targeted systems but also on the entire internet infrastructure. Due to the vast number of infected IoT devices, the Quality of Service of the target system can be severely hampered by DDoS attacks. Despite the severity...

Big Data Analytics is a critical function in Telecommunication Systems in order to monitor, measure and report the system’s performance for various services. Collecting data from various nodes, extracting the necessary fields, correlating the data according to system needs, storing the data and reporting the required information are the main functi...

Healthcare monitoring such as heart rate, oxygen saturation (SpO) and body temperature is used in various applications from consumer lifestyle practices to patient monitoring. It is essential to have secure data transfer from sensor to monitoring dashboard for healthcare monitoring. In this study, an encryption scheme is proposed for a healthcare f...

Developing a secured information processing environment highly depends on securing all of the layers and devices in the environment. Edge/Fog computing environments are not an exception in this case, and the security of those environments highly depends on securing the Internet of Things (IoT) devices which are the most vulnerable devices through t...

Users of communication applications always want uninterrupted and high-quality sound. It is possible to provide these requests by determining the quality experienced by the end-user. Under different network conditions, it is important to identify the effects of parameters and possible scenarios in order to select the most optimal Opus codec configu...

In telecommunication platforms, it is necessary to monitor the system, take quick action against possible and observed errors, and ensure the continuous operability of the system. However, debugging and problem addressing processes can take a long time in microservice architecture-based platforms with high number of users and heavy traffic. This di...

The business world is undergoing through a digital transformation, and the transformation driven by business needs to be faster, more agile and to better respond to customer needs. As a result, there has been a need to move communications environments and some computational workloads to one or more cloud environments. In this study, attack surfaces...

The invention is related to a system and a method for use in the telecommunication system that prevents the fraud activities made by using a method named as OTT (Over The Top) Bypass that causes loss of income to the telecom operators and customer dissatisfaction, by means of detecting abnormal OTT call via analyzing the network data structures of...

Invention relates to fraud detection system and method using enriched CDR (Call Detail Records), voice quality records, big data security analytics and machine learning algorithms for detection of fraud made by use of over-the top (OTT) Bypass method in call traffic outgoing from original operator where call starts.

VoIP is one of the most popular services of the communication world at today, and it is affecting and changing all telecommunication landscape. Because of its popularity, it is increasingly becoming a target in which to hide communications. One of the most popular steganography techniques is to use a covert channel, which may be dangerous to compan...

This work explores attack and attacker profiles using a VoIP-based Honeypot. We implemented a low interaction honeypot environment to identify the behaviors of the attackers and the services most frequently used. We watched honeypot for 180 days and collected 242.812 events related to FTP, SIP, MSSQL, MySQL, SSH, SMB protocols. The results provide...

Technological generation change have expanded the use of VoIP. In parallel to this expansion, exploiting the vulnerabilities of the VoIP systems have increased. Fuzzing test are widely used in the discovery of these vulnerabilities. In our study, we discuss the discovery of vulnerabilities of SIP based VoIP system with Fuzzing test and the exploita...

The invention generally relates to a method for calculation of information and information source (1) reputation to be used in a "scalable" size Security Operation Center (SOC), which provides a significant infrastructure for prevention of cyber attacks, and which can be flexibly adapted to the needs of institutions.

One of the most effective defense mechanisms against threats is to establish threat intelligence platform and early warning systems and to understand the adversary’s behavior, capability, and intent. Threat intelligence and early warning systems require collaboration among legitimate participants which have cyber security solutions and trustworthy...

In telecom technology, 4G days are experienced and preparations for 5G are made. Technological generation change and the expansion of IPv6 have increased the use of VoIP. In parallel to this increase, we are faced with many frauds and weaknesses. To find the vulnerabilities of VoIP systems, detect attacks against these systems and protect them, the...

VoIP services have become a major competitor to the PSTN networks. Performance and security of the authentication and key agreement schemes are two critical factors that affect the VoIP applications with large number of users. The authentication mechanism of SIP protocol is based on the HTTP Digest Authentication. This mechanism is easy to implemen...

WebRTC (Web Real-Time Communications) is an open source technology promoted by Google and standardized under the coordination of the W3C and IETF. It was originally designed to have a browser-to-browser real-time communications however it is also possible to adapt web-based communications with other IP-based or legacy networks through gateways. By...

VoIP services have become a major competitor to the PSTN networks. Performance and security of the authentication and key agreement schemes are two critical factors that affect the VoIP applications with large number of users. The authentication mechanism of SIP protocol is based on the HTTP Digest Authentication. This mechanism is easy to implemen...

The Rijndael is a block cipher with variable block and key size. The Rijndael with 128 bit block size is adopted as the Advanced Encryption Standard (AES) in 2000 and has become widely used in the bulk data encryption. This work investigates the ecien t implementations of the Rijndael for the 32 bit resource limited mobile devices using Java 2 Micr...