Basically a compiler "rootkit". I found this comment interesting: "At some point, aboveboard modifications to the compiler or login program might get to the p

Basically a compiler "rootkit". I found this comment interesting: "At some point, aboveboard modifications to the compiler or login program might get to the point where they defeat the backdoor's compiler-recognizer/login-recognizer, and subsequent iterations would lose the backdoor. This is analogous to a random biological mutation granting immunity to certain diseases."