On the dangers of speaking outside your area of competence

Ok, this is just dumb. According to this article, Richard Carrigan, a physicist at Fermilab, is concerned that aliens (as in E.T.) are going to "infect the Internet". He claims that the signals processed by the millions of computers participating in the SETI@Home distributed computing project are capable of carrying malicious code, and the SETI project should implement some sort of signal quarantine to protect us. Kind of like a reverse Jeff Goldblum manoeuver from Independence Day.

The thing is, this isn't a very likely scenario. First, the signals are data, and not executable code. That's our first layer of protection.

Now, we could posit a software flaw in the SETI@Home client that could lead to some sort of overflow that allowed arbitrary code to be executed, but in order for aliens to successfully exploit it, they'd need to know an awful lot about how our computers work, and about our current software versions, and the laws of physics are working against them.

The closest star is about 4.5 light years away from Earth. Assuming that we broadcast complete technical details of the x86 architecture and an entire copy of the Windows OS, along with a comprehensive set of security bulletins and an SDK, the necessary roundtrip time for data travelling at the speed of light would mean that by the time the "exploit" could arrive here, we'd be about 9 years further on. Let's see, 9 years ago, we'd all have been running NT 4 and Windows 95. Good luck trying a Win95 overflow on my XP system! The offsets are wrong now, and new security technologies exist now that weren't dreamed of then (like the non-executable stack). What will we have 9 years from now? I don't know (and neither do the aliens), but I do know the aliens don't stand a chance.

Seriously, I think he's missing the point. If you want to be concerned with the security of the SETI@Home software or their new replacement, BOINC, don't bring aliens into the picture. Security concerns are legitimate, yes, but it is far more likely that if a software bug does exist that allows remote code execution, it'll be exploited by a human, not an alien.

Unless, of course, you believe this guy.

Update 2005-11-28 09:48 -- Check out Richard Carrigan's website for more information on his idea. There's a presentation and a copy of his paper on the subject.