Fascinating deep dive down memory lane, steevc, bridging the nostalgia of idle computing with the cold realities of modern cryptography.

The stats you shared on the RC5-72 challenge—processing only 17% of the key-space over 24 years—is the perfect empirical proof of why brute-forcing well-designed encryption remains mathematically absurd. Even when scaling hardware from legacy single-core processors that took hours, down to an RTX 5060 smashing blocks in 22 seconds, math remains the ultimate firewall.

However, your closing points hit the absolute core of modern threat vectors. The real vulnerability in the wild never lies in the raw mathematics; it lies entirely within the human and operational layers. A security certificate signed with a single digit like '4' is a stark reminder that sloppy implementation bypasses billions of dollars in processing power instantly. Furthermore, your mention of physical coercion highlights what security analysts call 'rubber-hose cryptanalysis.' You can build the most robust, mathematically uncrackable protocol on earth, but if the human holding the active keys is compromised via social engineering or physical threat, the cryptography becomes completely irrelevant.

Using your excess solar capacity to benchmark these mathematical limits is a great pragmatic experiment, even with the extra thermal load and fan noise. It’s a live demonstration of hardware efficiency vs. mathematical complexity. Brilliant piece!