Asymmetric Physical Layer Encryption for Wireless Communications

In this paper, we establish a cryptographic primitive for wireless communications. An asymmetric physical layer encryption (PLE) scheme based on elliptic curve cryptography is proposed. Compared with the conventional symmetric PLE, asymmetric PLE avoids the need of key distribution on a private channel, and it has more tools available for processing complex-domain signals to confuse possible eavesdroppers when compared with upper-layer public key encryption. We use quantized information entropy to measure the constellation confusion degree. The numerical results show that the proposed scheme provides greater confusion to eavesdroppers and yet does not affect the bit error rate (BER) of the intended receiver (the information entropy of the constellation increases to 17.5 for 9-bit quantization length). The scheme also has low latency and complexity [<inline-formula> <tex-math notation="LaTeX">$O(N^{2.37}) $ </tex-math></inline-formula>, where <inline-formula> <tex-math notation="LaTeX">$N $ </tex-math></inline-formula> is a fixed block size], which is particularly attractive for implementation.