omphalaskepsis comments on Who wrote this software? An Ex-CIA agent?

omphalaskepsis comments on Who wrote this software? An Ex-CIA agent?: "Let me tell you a little story. In 1983, during his Turing Award lecture, Ken Thompson admitted to a back door in the UNIX kernel which enabled him to log in. Because UNIX was distributed as source, he was concerned about being discovered. So instead he wrote the C compiler to recognize that it was compiling the kernel, and to insert the relevant code into the binary during compilation. But because the C compiler was also distributes as source, he wrote the compiler so that it would recognize it was compiling a copy of itself, and then insert the relevant recognition code into the new C compiler. The result: a back door installed in an operating system distributed entirely as source code (without the back door)."