# Half a Day vs Five Months

The most dramatic data point for AI-assisted rigor: Stanford researcher Chuyue Sun used AI to formally verify part of Signal’s encryption code in under half a day for less than $500 — work that took three experts five months by hand. Days later, &Truth emerged from stealth with $70 million in seed funding to build a universal verification machine on the Lean proof system.

## Key facts

- Chuyue Sun used AI to complete part of a Signal encryption-code verification in under half a day and under $500 (reported October 29, 2026 by mogazmasr).
- The same work had taken three human experts five months by hand.
- &Truth emerged from stealth on Thursday with a $70M seed round to mathematically prove code correct.
- Per Dealroom, the round closed October 29, 2026; founders include Clark Barrett, Ilya Sergey, and Chris Hsu.
- The company's approach is built on the Lean proof system.
- The story reframes AI coding assistance: not just faster typing, but formal proof at a fraction of the expert cost.

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