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The Underhanded C Contest (underhanded-c.org)
2026-07-01 Wed | 79 points by ccabraldev | original
[−]AmazingEveryDay · 2026-07-01 Wed 22:47 UTC · link
(2015). RIP.
[−]gwern · 2026-07-01 Wed 22:56 UTC · link
[−]ForOldHack · 2026-07-02 Thu 05:40 UTC · link
Oh my god, and to think that OCC used to just be ways to torture the pre-processor... stunning work. Utter and complete no holds barred mud.
[−]TZubiri · 2026-07-02 Thu 00:05 UTC · link
2026 calls for an Underhanded prompt contest
[−]theteapot · 2026-07-02 Thu 00:56 UTC · link
Or better, sleeper agents. Anthropic released a study on this in 2024 "Sleeper Agents: Training Deceptive LLMs that Persist Through Safety Training" -- https://www.anthropic.com/research/sleeper-agents-training-d..., https://www.youtube.com/watch?v=_y9j2BoHg2c
[−]BiraIgnacio · 2026-07-02 Thu 00:55 UTC · link
> The contest was initially inspired by Daniel Horn’s Obfuscated V contest in the fall of 2004 (note: the original page is long gone, and this link goes to a snapshot from archive.org). The object of that contest was to write a simple program to count votes, that somehow miscounts the votes on election day. I was greatly impressed to see how even a short program to simply count characters in a text file can be made to fail, and fail only on one specific day, so that the bug isn't noticed in testing.

https://underhanded-c.org/_page_id_7.html

[−]silisili · 2026-07-02 Thu 01:19 UTC · link
The original page actually loads fine, maybe was restored later?

I looked through a few trying not to read the short description and missed a lot of simple things, really makes you think...

https://graphics.stanford.edu/~danielh/vote/vote.html

[−]pseudohadamard · 2026-07-02 Thu 03:21 UTC · link
Interesting that the case they were using was the Nuclear Threat Initiative and FP uncertainties, I've audited some, ah, nuclear-physics-related code that had an issue due to FP uncertainties...
[−]ForOldHack · 2026-07-02 Thu 05:41 UTC · link
Where you can encode an entire Command and Control server within rounding errors! You sneaky skunk!