> since when does u2a protect against back-end breaches? It doesn't have to. For 99.999% people, the two most realistic threats are: * There is a keylogger on

> since when does u2a protect against back-end breaches? It doesn't have to. For 99.999% people, the two most realistic threats are: * There is a keylogger on some computer where you access your Dropbox, for example at a print shop, * You use the same password on many sites, one gets compromised, and automated bots try to access your Dropbox account.