The Underhanded C Contest

The 2015 Underhanded C Contest challenged programmers to write deceptive C code for a nuclear verification application, receiving over 40 high-quality submissions. About one-third of entries exploited a "NaN poisoning" vulnerability, where floating-point "not a number" values are introduced through unusual computations and then propagated through comparisons to bypass security checks. The contest, sponsored by the Nuclear Threat Initiative, highlights the critical need for careful, rigorous software development in security-sensitive applications.