monline

I'm going to add (or at least design) digital signature support for my company's application framework and I read through the Wikipedia article on digital signatures to freshen up things a little bit. The last paragraphs talk about use of smart cards with dig. signatures. They say that smart cards are one of the most widely used methods for securing private keys for everyday use. This made me think a little bit.

The whole thing about private keys is identification. We assume that the keeper of a private key is the only entity (let's say for now it's a person) possessing that key. However a smart card is not part of a person ... it's a separate gadget that one can steal, temper with, etc. The use of a PIN code to access the contents of the smart card is not secure enough. One could watch you through a binocular typing in your PIN code, etc.

So what might be the ultimate method for identification? We need something that is unique for every person ... something that is "part" of that person, thus it cannot be removed, neither reproduced. All currently used biometric identification methods are not good enough. You could say: let's use a fingerprint or a retina scan as basis for a private key ... but that'd be wrong of course. These are all static attributes of a person and the digital representation of a fingerprint (or a retina scan) could be stolen and used maliciously too. We need something interactive, but still unique thing.

What about the brain? The human brain consists of billions of neurons and is pretty much unique to each individual (even identical twins have different neural networks). It's complex enough (maybe even too complex) for our aims and is definitely not replicable (at least up til now nobody could "copy" a brain).

There're already a number of projects under development (for various purposes starting with medicine and including military as well) on building interfaces between the brain and computers (or more simplified: electronic devices). Eg. a lot of research is put into "mind-control" of various devices (robotic arms, wheelchairs, ..., combat vehicles, etc.). What if we used the brain as a source of identification? I think of some property of the brain that cannot be reproduced without reproducing the complete brain. I think of some challenge-response interaction: we could produce some random input to the brain and the response would be random as well, but unique to the input+brain pair.

The idea seems to be good, but the implementation has a "few" difficulties. Currently even the most promosing "brain-interfaces" include some wiring ... thus physical contact. To make this usable, some sort of "wireless brain interface" should be developed, which is still something for the sci-fi movies.

I wonder whether this will be achieved at all? If yes, it means telepathy is in reach too. An intermediate solution could be a small device (just a few milimeters in size) that we could wear on our skin (just like a sticker) and take off anytime. It could be powered by our bio-electricity and include some wireless transmitter.

Honestly ... would it be not cool if you could have a phone call without even opening your mouth?