@djb this reminds me of the Star Trek episode with Data and the Zakdorn [https://memory-alpha.fandom.com/wiki/Peak_Performance_(episode)] where Data keep losing until he switches his strategy to a draw instead of a win. Only at that point does he not immediately lose, leaving the Zakdorn to quit in frustration. Play for the draw. [P.S.: I have zero fucking clue about cryptography, quantum or regular.]