Low-Complexity Encryption Using Redundant Bits and Adaptive Frequency Rates in RFID

In this work, we propose a low-complexity encryption used in a passive Radio Frequency IDentification (RFID) transponder. The proposed encryption functions by using redundant bits and adaptive frequency rates in the transponder to dynamically change the number of the transmitted bits and operation frequencies. The pseudo-random bit sequence is generated by the linear feedback shift register to represent the redundant bits. Additionally, the ring oscillator with a divider and a multiplexer produces a programmable operation frequency. Such approach not only protects the transmitted data under fairly low power consumption, but it also can integrate with the other encryption methods, such as the Advanced Encryption Standard (AES) and the Data Encryption Standard (DES), to further enhance security. Therefore, the encryption scheme proposed herein can be applied in various communication devices to achieve high-security and low-complexity performance.