Dennis Goeckel, Robert Jackson, and James Doty


The onset of quantum computing calls for secrecy schemes that can provide everlasting secrecy resistant to increased computational power of an adversary. We propose a scheme where 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. To support 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, has been 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. Ongoing work is focused on enhanced system design (e.g., multiplicative jamming), cryptographic analysis, and studying the resilience of the scheme to multiple independent adversaries.