Gövde alan ağlarının güvenliği için fizyolojik sinyaller kullanılarak sözde rasgele anahtarlar oluşturulması

With the help of recent technological advancements especially in the last decade, it has become much easier to extensively and remotely observe medical conditions of the patients. This observation is done through wearable devices named "biosensors" that act as connected nodes on the Body Area Network (BAN). The main goal of these biosensors is to collect and provide critical and sensitive health data concerning the host individual, communicate with each other in order to make decisions based on what has been captured and relay the collected data to remote healthcare professionals. The sensitive nature of this critical data makes it extremely important to process it as securely as possible. Biosensors communicate with each other through wireless medium that is vulnerable to potential security attacks. Therefore, secure mechanisms for both data protection and intra-BAN communication are needed. Moreover, these mechanisms should be lightweight in order to overcome the hardware resource restrictions of biosensors. Random and secure cryptographic key generation and agreement among the biosensors take place at the core of these security mechanisms. In this thesis, we propose SKA-PSAR (Secure Key Agreement Using Physiological Signals with Augmented Randomness) system. The main goal of this system is to produce highly random cryptographic keys for the biosensors for secure communication in a BAN. Similar to its predecessor SKA-PS protocol by Karaoğlan Altop et al., SKA-PSAR also employs physiological signals, such as heart rate and blood pressure, as inputs for the keys and utilizes the set reconciliation mechanism as basic building block. Novel quantization and binarization methods of the Secure Key Agreement Protocol of the proposed SKA-PSAR system distinguish it from SKA-PS in a way that the former has increased the randomness of the generated keys. In addition, the generated cryptographic keys in our proposed SKA-PSAR system have distinctive and time variant characteristics as well as long enough bit sizes that can be considered resistant against a cryptographic attack. Moreover, correct key generation rate of 100% and false key generation rate of 0% have been obtained. Last but not least, results of the computational complexity, communication complexity and memory requirements of our proposed system are quite higher as compared to SKA-PS, but this is a cost that needs to be paid for achieving high randomness level.