Thompson's Trojan Compiler

Question

I\'m trying to grasp a better understanding of Thompson\'s Trojan Compiler (discussed in his 1984 ACM Turing Award speech \"Reflections On Trusting Trust\"), and so far this is

Answer 1

Yes, it is the right concept. There's more to it; the modified compiler must also compile the unmodified compiler source to a similarly modified copy of itself. This includes trivial variations of that source, which basically means the modified compiler has to be able to solve e.g. the halting problem.