Reflections on Trusting Trust
Ken Thompson. 1984. (View Paper → )
The relevant parts of the abstract can be copied here in italics...
As a programmer, I write programs. I would like to present to you the cutest program I ever wrote. I will do this in three stages and try to bring it together at the end.
This paper showed just how hard it can be to spot exploits in code you haven’t written. The author therefore concludes that you can’t trust code you haven’t written.