In the past few years, several encryption algorithms based on chaotic systems have been proposed as means to protect digital images against cryptographic attacks. These encryption algorithms typically use relatively small key spaces and thus offer limited security, especially if they are one-dimensional. In this paper, we proposed a novel image encryption algorithm based on Rubik's cube principle. The original image is scrambled using the principle of Rubik's cube. Then, XOR operator is applied to rows and columns of the scrambled image using two secret keys. Finally, the experimental results and security analysis show that the proposed image encryption scheme not only can achieve good encryption and perfect hiding ability but also can resist exhaustive attack, statistical attack, and differential attack.
Information security is becoming a critical challenge in wireless communications due to the open nature of wireless channels and the transparency of standardized transmission schemes. Among the various wireless security techniques, user authentication is one essential measure to identify legitimate users and protect the integrity of transmissions. In this paper, a novel physical layer authentication scheme is proposed to enhance the communication security by exploiting the unique characteristics of oscillator in each communication device. In realistic scenarios, radio frequency (RF) oscillators in each transmitter and receiver pair always present some bias to the nominal carrier frequency due to manufacturing limitations and operating conditions. This bias is characterized by a device-dependent carrier frequency offset (CFO), which can be used to identify a specific wireless transmitter. In the proposed authentication scheme, the CFO at different time of the received signal is first estimated. It is then examined by a hypothesis testing to determine whether the signal has the consistent CFO for authentication purpose. Adaptive thresholds of CFO variation are derived for user discrimination based on the received signal-to-noise ratio (SNR). Simulation results further confirm the effectiveness of the proposed scheme in multipath fading environments.
A new position location technique using the transmitter identification (TxID) RF watermark in the digital TV (DTV) signals is proposed in this paper. Conventional global positioning system (GPS) usually does not work well inside buildings due to the high frequency and weak field strength of the signal. In contrast to the GPS, the DTV signals are received from transmitters at relatively short distance, while the broadcast transmitters operate at levels up to the megawatts effective radiated power (ERP). Also the RF frequency of the DTV signal is much lower than the GPS, which makes it easier for the signal to penetrate buildings and other objects. The proposed position location system based on DTV TxID signal is presented in this paper. Practical receiver implementation issues including nonideal correlation and synchronization are analyzed and discussed. Performance of the proposed technique is evaluated through Monte Carlo simulations and compared with other existing position location systems. Possible ways to improve the accuracy of the new position location system is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.