After a few weeks of work, I finaly release my version of a bitcoin stock exchange plateform.
It's kind of a proof of concept, but it's for real, as I have already to owners of two shares (one eBay share and one DRDGold share).
Ownership is identified by the bitcoin address where dividends are to be paid. Nothing else : no GPG key, no DSA key, nothing but the paiement address for future dividends.
The site allows an owner to transfer some shares to an other bitcoin address, and thus to an other person.
Once transfer is possible, trading is possible. But so far I don't offer any book keeping for order. Trading and negociation must then be handled somewhere else (IRC, forum, biddingpond, whatever...)
Making a signature for transfer requires the use of bc_key, written by dirtyfilthy. I whish this app was added to the main bitcoin client, but I suspect the dev-team is not keen on doing so.
The site is open source, so anyone could do exactly the same.
That's about it. Here is the address :http://grondilu.freeshell.org/brokerage.cgi