(A response also to jkaljundi)
> Could you elaborate
Since you get a PIN card with a private key, someone else generated it. Whoever did it could impersonate me. I guess it would be done by a private company, so at least that company can do it. But I'm pretty certain that something of this importance would be accessible to a government (no real arguments here, merely armchair discussion)
It's true that only concerned parties know about the transaction... until the transaction is made public (or shared with other interests). Again, I'm pretty sure this will be one way or another visible to the government.
You could say I'm paranoid and anti-government. I just think that being paranoid is a necessary thing when doing anything related to security, and this falls exactly in this topic. The very least, as iwwr points out, is that anyone could create their own private key in this system (ie associate the generated public key with the id given by the government). The secrecy of the transactions is yet another problem which basically boils down to "how much do you trust other parties", and has little to do with technology.
The idea of being able to do everything, including voting, with your computer is an amazing thing, but to date very little has been done to make sure that citizens can expect the same as today in terms of secrecy, privacy and ease of use. Again, a matter of how much you are paranoid and how much you are wanting to give up security in order to make things simpler.
Thanks for the link, I will have a look.
> So strangers are very welcome to apply for a personal ID code in Estonia
Well, that's very good news :)