Examination Regarding the Concealment of Watermarks in the Oscillator Phase Noise of Binary Phase Shift Keyed Signals

Watermarking provides an additional way to authenticate users in a stealthy way. This thesis investigates the possibility of hiding constellation dithered watermarks within oscillator phase noise of BPSK modulated signals. Message bit error rates and watermark bit error rates are compared for different phase noise standard deviations and watermark positions. Goodness of fit tests utilizing the Lilliefor’s test, are conducted to determine if the investigated watermarking method can be considered stealthy.Electrical Engineerin

Physical Layer Watermarking of Binary Phase-shift Keyed Signals Using Standard Gnu Radio Blocks

This thesis discussed the development, implementation, simulation, and testing of a physical layer watermarking method. The method was to use pre-existing GNU Radio building blocks. The main goal of the project was to implement a watermarking method using GNU Radio with the USRP software radios which could also be implemented using standard communications hardware so implementation on SDR systems as well as pre-existing communications systems was possible. Simulations of the physical layer watermarking system were created using a Monte Carlo method. The generation of a probability distribution of phase difference error was appropriate to analyze the expected performance of the DPSK watermarking system developed. Testing was performed in a realistic office environment where interference in the tested frequency band was common. A stationary receiver gathered data from a transmitter at various locations and power levels. The bit error rate of the gathered data was determined to analyze performance. While the testing in a real world environment had a limited range of valid analysis due to limited sampling time and interference, the results were comparable with the simulations. Testing and simulations showed the proposed physical layer watermarking method has the potential to compete with the performance of other authentication focused watermarking methods. In addition, the proposed method could be used to provide a separate, possible secretive, data channel under certain circumstances. An important benefit of the proposed watermarking method is its ability to be implemented in many SDR or traditional communication systems with no hardware modifications.School of Electrical & Computer Engineerin

IEEE 802.11 i Security and Vulnerabilities

Despite using a variety of comprehensive preventive security measures, the Robust Secure Networks (RSNs) remain vulnerable to a number of attacks. Failure of preventive measures to address all RSN vulnerabilities dictates the need for enhancing the performance of Wireless Intrusion Detection Systems (WIDSs) to detect all attacks on RSNs with less false positive and false negative rates

Robust watermarking and its applications to communication problems

Digital watermarking has recently gained an intense interest in research and applications. An invisible and secret signal, called watermark, is added to the host data. With the help of this watermark issuer of the data can be unveiled, unauthorised users can be identified, illicit copying can be avoided, any attempt to temper with the data can be detected and many other security services can be provided. In this thesis, the relations and differences between watermarking and communication systems are elaborated. Based on these results new methods for both watermarking and communication are derived. A new blind, robust and reversible watermarking scheme based on Code Division Multiple Access (CDMA) is presented in this thesis. Using this scheme watermark is arithmetically added to spatial domain or frequency domain. Watermark is extracted by using spreading codes only. Proposed watermarking scheme is simple, computationally efficient and can be applied to any image format. A novel idea that watermark can be part of the image is presented. By using watermark, which is a part of an image, digital watermarking can be used beyond simple security tasks. A part of an image is selected and embedded in the whole image as watermark. This watermarked image is attacked (transmitted or compressed). By using the extracted watermark and attacked selected part image quality can be assessed or jpeg quantization ratio can be estimated or even image can be equalized blindly. Furthermore, CDMA based watermarking is used to authenticate radio frequency signal. Spreaded watermark is added in the form of noise to the modulated radio frequency signal. If this noise is increased, watermarked signal automatically becomes a scrambled signal. Later watermark is extracted and by using reversibility of proposed scheme watermark is removed. Once the watermarked is removed original signal is restored, hence descrambled