Yes, it is well presented RobertLloyd.
Jon Matonis of the Bitcoin Foundation and a columnist for Forbes also wrote on this subject of Nemo dat quod non habet.
Edit: here is the Jon Matonis blog on the subject including a couple of other informative articles on the subject linked within:
Jon cited case law that was the opposite of Nemo dat quod non habet regarding money so that someone receiving money in good faith not knowing it had been stolen did not have to return money to a person earlier robbed of it.
Nemo dat quod non habet applies to distinctly identifiable things like the art works stolen by the Nazis during WWII, or any identifiable artwork for that matter, but less identifiable items like common jewelry and diamonds naturally fade into exclusion with their increasing inability to be distinctly identified.
I think case law is undecided on this matter in re Bitcoin because it has not been decided exactly what Bitcoin is. It probably will make new law. But the public ledger traceability does not augur or bode well in bitcoin’s favor as RobertLloyd indicates.
Cryptocurrencies may have to adopt an anonymizing feature in the future such as for example the zerocoin protocol. One step at a time.
Bitcoin not only has the 744K mtgox problem, but there is also the 96K stolen recently and the 450K or so that the FBI knows went thru Silk Road but the FBI doesn’t have the keys to so they can’t immediately seize the coin. Surely, they have software tracing these coins by now. And what about when coins are divided and recombined some part tainted and some part not? And tumblers? And coinslinger?
The good news is so far as I know Peercoin has pretty much been free from piracy, theft and known illegal dealing but it is highly important that security be beefed up as much as possible because as Peercoin value rises the desire to steal it will rise also. I think malware will become dramatically more sophisticated and intrusive over the immediate coming years because of the stealable nature of cryptocurrencies.
The blockchain protocols have so far been remarkably secure but the end points, i.e. user’s machines, are weak. I believe this is where we need to really work on improving security.