By utilising the option to do this: http://en.wikipedia.org/wiki/Mind_uploading
I think that anyone would be stupid to suggest that this won't be possible in the future. People will be uncomfortable with it and it won't be widely adopted for along time, but within 1000 years (perhaps more than half that timeframe) I believe all personal digital assets will be stored in the mind.
Either: regulations will mean that you can't escape it, like in Minority Report, or it will just be so normal to people by then that it won't be an issue, and people see it as the preferable method of storage and usage.
Mind recognition would be available for transactions. This could still be an anonymous act - no machine would actually need to know who you are, because it will just be matching your brain composition to your wallet, very much like a fingerprint. Your brain would just be an HD but with a unique structure, but an anonymous unique structure. You would not be giving up your details, you are simply another number to the network and it recognises your brain pattern on its database, which is synced to your wallet (which happens to be stored in your brain).
Way way into the future though...