Sunday, March 07, 2004

Ethical Considerations in Quantum Computation

I was going to comment on President Bush's Bioethics Council, but then I thought I should start closer to home.

I have a Ph.D. in Electrical Engineering, which generally means that I am either a professor or a researcher. In my case, I am a researcher who runs experiments and analyzes the data. My area of research is quantum computation, as you may have figured out from other things I've said around here. Quantum computation has its own ethical dilemma. To date, we've discovered that it's very good at two useful applications, performing unordered searches and factoring large numbers. The first may be useful, while the second is definitely useful. It's much easier to find a prime number and multiply it by another large prime number than to factor a large product of primes. When I say much easier, I'm talking about it taking the same computer a few seconds to do the finding and multiplying, versus a few million years to do the factoring. This sort of one-way problem forms the basis for public key encryption (although it is of course more complicated than that), such as that used in RSA, the encryption protocol used to transmit information on the Internet. For more information on RSA, check this FAQ from the sci.crypt newsgroup. A quantum computer with a sufficient number of qubits could factor a large product of primes faster than a classical computer create it in the first place. If someone were to produce such a computer today, all Internet transactions would suddenly be vulnerable.

You can tell what use people are planning for a quantum computer by looking at where the funding is coming from. Right now, the people giving out the funds are the Army Research Office, the Defense Department, and, oh yes, the NSA. It's clear that the main objective is decryption (or, perhaps, to prove that a quantum computer is so far from realizable that public key encryption is secure).

In my experience, very few scientists working on quantum computation projects think about the ethical implications at all. For the most part, they console themselves with the fact that a quantum computer capable of factoring a decent sized key is so far in the future that by the time it gets here (~25 years or so), we'll have better encryption (hopefully, quantum encryption). That may or may not be the case. I've heard that the federal government may be pushing for a five-year program to develop a quantum computer that can factor 128-bit encryption. (I've been looking for confirmation but I haven't found it yet.) This is wildly ambitious--I don't think it will happen--but how many scientists, who previously considered quantum computation safe because it was decades away, would jump at the chance to partake of this funding?

For the record, I have thought a bit more in-depth about quantum computation, partially because I took part in a discussion group with MIT's Graduate Christian Fellowship based on the book Responsible Technology. To a large degree, the questions about developing a quantum computer revolve around who would get it. Quantum computers aren't going to be available on the open market anytime soon, and they'll probably be as regulated as nuclear power. So, assuming I helped create a quantum computer, would I trust the NSA to use it wisely? I certainly don't mind them cracking a terrorist's e-mail, but I wouldn't want them reading mine. So, I don't think that the technology itself is wrong, but I am concerned over how it would be used.

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