Because no one's that worried about people confiscating their cars, while there are demonstrable concerns about gun confiscation. Of course, unlike a registry of the guns themselves, a database of people with gun licenses would not have a 1:1 correlation with guns owned. (And I'm sure there would be people encouraging anyone who doesn't intend to buy a gun to get the license anyway, which would "foul" the database for that use without inhibiting any of it's legitimate purposes.)
In a perfect world, you could probably make licenses verifiable via digital signatures without requiring a database for comparison, but even if the math is there, I'm not sure I'd want to rely on a large-scale licensing authority to keep the private keys secure. (Although I'm under the impression that there's various ways to reduce exposure risk in that sort of thing, but it gets way over my head.)
-Morgan.
In a perfect world, you could probably make licenses verifiable via digital signatures without requiring a database for comparison, but even if the math is there, I'm not sure I'd want to rely on a large-scale licensing authority to keep the private keys secure. (Although I'm under the impression that there's various ways to reduce exposure risk in that sort of thing, but it gets way over my head.)
-Morgan.