Speed up wallet sync (without compromising on security or privacy)

[john-light]

If I haven't used zk.money in a while, it takes a minute or two (or sometimes longer, it seems) to sync the wallet when I open it up.

I have been told that one way the Aztec team is thinking about addressing this is with a "sharding-based" approach. I'd be interested in learning more about the ideas here.

Another idea I have is to enable users to run their own Aztec full node outside of the browser, on a personal server in their home (like DAppNode) or somewhere in the cloud, and then pair their zk.money wallet with their externally-operated full node so that when they open the wallet, its balances are synced right away (since the externally-operated node is running 24/7 and so always synced with the chain tip).

Regardless of the method used, I can see this sync time getting longer and longer as the rollup fills with more transactions, and so for the sake of UX we'll want to figure out one or more solutions so that users can open their wallet and begin using it within a reasonable amount of time without compromising on security or privacy (i.e. no "trusted third party servers" doing the heavy lifting here).