  Cyber defense is reactive and slow. On average, the time-to-remedy is
hundreds of times larger than the time-to-compromise. In response to the
expanding ever-more-complex threat landscape, Digital Twins (DTs) and
particularly Human Digital Twins (HDTs) offer the capability of running massive
simulations across multiple knowledge domains. Simulated results may offer
insights into adversaries' behaviors and tactics, resulting in better proactive
cyber-defense strategies. For the first time, this paper solidifies the vision
of DTs and HDTs for cybersecurity via the Cybonto conceptual framework
proposal. The paper also contributes the Cybonto ontology, formally documenting
108 constructs and thousands of cognitive-related paths based on 20 time-tested
psychology theories. Finally, the paper applied 20 network centrality
algorithms in analyzing the 108 constructs. The identified top 10 constructs
call for extensions of current digital cognitive architectures in preparation
for the DT future.
