Noise-enhanced encryption for physical layer security in an OFDM radio

• Published in: 2009 IEEE Radio and Wireless Symposium pp. 344 - 347
• Main Authors: Reilly, D., Kanter, G.S.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.01.2009
• Subjects: communication system security; Constellation diagram; Cryptography; military communication; OFDM modulation; Optical modulation; Optical noise; Optical transmitters; packet radio; Physical layer; pseudonoise coded communications; radio communications; Radio link; Random number generation; Security
• ISBN: 9781424426980; 1424426987
• ISSN: 2164-2958
• DOI: 10.1109/RWS.2009.4957350

We adapt a physical-layer modulation scheme previously used for enhancing security in the optical domain to an OFDM radio link. The method relies on manipulating the signal constellation according to a cryptographic pseudo-random number generator and adding a small amount of truly random noise at the transmitter. We test the ultra-secure format by generating modified 802.11a packets offline and transmitting them over-the-air using a radio board designed for software defined radio applications. Our initial test system uses an underlying QPSK data format with a 12Mb/s burst-mode data rate. No performance penalty was observed by adding the noise-enhanced encryption function.