[JaimeThompson]

Except humans haven't developed ways to write bug free code except in a very few limited circumstances none of which crypto uses.

[unemphysbro]

hence the recent renaissance in formal methods

eg.

https://www.certik.com/

[exdsq]

Formal methods doesn't necessarily mean that you're building the right thing which catches quite a few projects out. I do really enjoy getting to work with them though :D