Analog Cancellation of a Known Remote Interference: Hardware Realization and Analysis

The onset of quantum computing calls for secrecy schemes that can provide everlasting secrecy resistant to increased computational power of an adversary. One novel physical layer scheme proposes that an intended receiver capable of performing analog cancellation of a known key-based interference would hold a significant advantage in recovering small underlying messages versus an eavesdropper performing cancellation after analog-to-digital conversion. This advantage holds even if an eavesdropper later obtains the key and employs it in their digital cancellation. Inspired by this scheme, a flexible software-defined radio receiver design capable of maintaining analog cancellation ratios over 40 dB, reaching up to and over 50 dB, is implemented. Using analog cancellation levels from the hardware testbed, practical everlasting secrecy rates up to 2.0 bits/symbol are shown to be gained by receivers performing interference cancellation in analog rather than on a digital signal processor.