HellGates, custom CPU gate-level challenge

A custom 32-bit CPU challenge called HellGates, designed with gate-level obfuscation and anti-tamper measures, remained unsolved by humans and multiple LLMs for over a year until GPT-6 solved it in under 30 minutes in September 2026 using side-channel analysis to exploit weak cryptography protecting the CPU's state. The challenge featured a virtual CPU architecture with 16 general-purpose registers, signed integer operations, and a 1GB encrypted memory that GPT-6 successfully decrypted and dumped after removing obfuscation layers.