DNA Encryption

brn writes "There is this BBC article that talks about hiding information inside the DNA. Very interesting and well worth a read, apparently information hidden this way is virtually undetectable. " It's the espionage agencies that first got interested, but the notion of "watermarking" is another that is brought up-and you thought PIII ids were bad.

Comments

Nothing earth-shattering here

[Kaa]

OK, in crypto language what we have here is a symmetric, secret key system where the key is the marker sequence at the ends of the DNA chain (I'm assuming the coding of the message into four bases is trivial). To put it into a more commonplace form, imagine taking your plaintext, encoding it into, say, the lower bit of 3 seconds of an audio CD recording, putting it into the middle of an audio CD and then sending it to the recipient. The key is knowing which 3 seconds to decrypt. Accordingly, you need a secret key which tells you: when you see a, say, 0x6a6c7ff45c054 sequence, start decoding. The advantage of using DNA is that your "CD" is very very long, but you can compensate for this in a variety of ways.

So, while this whole thing sounds cool, cryptographically this is nothing new and has no particular advantages (all the problems of dealing with secret symmetric keys, etc.). No wonder the NSA was not interested.

Kaa

No need for watermarking people

[Kaa]

You and a lot of other posters forget that there is absolutely no need to watermark people -- everybody is already "watermarked".

Consider this: to watermark a person you need to access his DNA and insert a watermark, then access it again to read it. Well, if during the first time you just read his DNA (which is unique) and the second time read it again and compare to a database -- voila! exactly the same result without all the unpleasantness of invasive DNA surgery. Why do you think reasonable people get worried when the police decides to take DNA samples from everybody arrested? (I don't know if the law/regulation to that effect passed in New York, but was definitely considered).

Kaa

Re:I like the BBC

[Stephen Williams]

I think European media in general is so much better because they are sponsored by the state.

You've got to be kidding me! So you're saying 'govermental' interests are better than commercial?

"State sponsorship" != "state control".

The BBC is funded by the state in that we have a "television tax", referred to as the TV licence fee. If you want to have a television, you pay a fee to the government. I forget how much it is (I direct debit all my bills :-) The revenue from this fee funds the BBC's television and radio programming. Apart from this, the state doesn't interfere. The BBC's programming isn't funded commercially at all; there are no ad breaks in BBC programmes. BBC subsidiaries (such as the excellent Radio Times magazine) are commercial, and do carry adverts.

This isn't the first time that I've heard Americans saying that they are impressed with European news reporting. If you have cable TV, see if you can get BBC News 24. I think you'll be pleasantly surprised by the quality of BBC TV journalism.

Re:Mutations

[Stephen Williams]

What if the DNA gets X-rayed and the message mutates? "Assault on target zero to begin at dawn" could become "Killer wombat found on moon" :-)

BBC licence fee

[Stephen Williams]

How exactly do they know that you have a TV to charge you the tax.

They have vans with TV detection equipment in. I don't know how it works; I guess it can detect UHF receiving equipment somehow. If they detect a TV in your house, and you haven't paid, you can get slapped with a hefty fine.

BTW: Owners of black and white TVs are charged a lower fee, and TV receivers which don't display a picture (sound only, for blind people) aren't taxed at all.

Re:DNA Storage Capacity

[hey!]

According to the human genome project, they will be establishing markers every 100K (1x10^5) base pairs, and will need 30K (3x10^4) of these markers.

That works out to 3 billion (3x10^9) base pairs.

Each base pair is made up of one or two pairs of units; if we distinguish sense from antisense strands in the DNA, this means we can encode four values (or two bits) of information per base pair, working out to 6x10^9 bits, or a little more than 5.5 GB (note that since only one side of a strand is used in life, this means you can spell "human" in the genetic sense in less than 2.5 Gbits).

As somebody else pointed out, this scheme is not encryption, but a method of information smuggling. That is, instead of using it to send secure messages over an insecure channel, the technique is supposed to hide the fact that a message even exists.

Although virtually undetectable by casual inspection, it's hard to think of a practical application of this technology because of the effort and equipment needed to extract the message. Sending detailed plans for sabotage to your terrorist cell this way seems impractical, unless your terrorists are biologists with lots of time on their hands.

Oh, calm down everybody

[whuppy]

This article is so content-free, it hardly
bears comment except for the hysteria it seems
to be inducing.

First of all, the technology described here --
synthesis of DNA oligomers and use of the polymerase chain reaction (PCR) to detect
them -- is old hat. Every molecular biology lab in the world has been using these techniques
routinely for over 15 years.

Second of all, coding DNA into something
biologically "meaningful" is orders of
magnitude more difficult than spelling out a message.

Finally, you all already can be uniquely identified by your DNA. Nobody needs to implant an ID in you, Big Brother can just take a drop of blood from you and store your DNA fingerprint in a database if he thinks you're worth looking after.

In closing, I would urge everyone not to look at biology (or even bioinformatics) through a hacker's eyes -- it doesn't work; the two fields don't map to each other well.

Oh, PS: If you want to see something genuinely cool being done with DNA by a hacker, check out Adleman's (the "A" in RSA) tackling the travelling salesman problem with DNA oligomers. (Sorry I don't have a cite handy.)

Another Application

[Mr. Morden]

In last month's Asimov's Science Fiction magazine there was a story called Written In Bloodabout someone who develops this kind of a technology and uses it to inscribe passages of the Koran into the blood of believers. Since this would be passed down from parent to child it could be used to mark Muslims in a way that was impossible before. It raises some interesting ideas about uses for writing in the genetic code of humans. I recommend the story and the magazine in general.