Stephan Neuhaus <[EMAIL PROTECTED]> writes: > On Apr 28, 2008, at 23:56, Perry E. Metzger wrote: > >> If you have a rotten apple engineer, he will be able to hide what he's >> trying to do and make it look completely legit. If he's really good, >> it may not be possible to catch what he's done EVEN IN PRINCIPLE. > > Fred Cohen proved in 1984 in his "Computer Viruses, Theory and > Experiments"[1] that "Program P is a virus" is undecidable.
He needn't have bothered. All non-trivial properties of programs are undecidable. Rice's Theorem, you know. Such a proof is one line -- you need merely assert that "X is a virus" is a non-trivial property (that is, a property that is only true of some programs). Perry --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]
