This is old news, but still, everyone should be aware of it. And on a theoretical basis, the co-creator of UNIX, Ken Thompson wrote a paper on which he explains that it is possible to add a backdoor to a closed source compiler and when you first compile any other compiler (e.g. GCC), any concequent compiles from this new compiler, would include the backdoor by default. Pessimistic thought of the day: nothing is safe. Neither Windows or Unix. I wonder how “safe” the Security-Enhanced Linux from NSA is. It might secure you from others, but does it secure you from NSA itself? ;P Update: More info here (Ms reply on the issue) and here.