Low security sync mode?

Question

I'm wondering if anyone has thought about or implemented a low security sync mode?

Presumably the client would only need to grab the TX hash, P and R values, and number of outputs, to be able to fully scan the whole blockchain for outputs that belong to them.

It would be low security because you would need to trust the node a little, however, unlike full light wallets (MyMonero), the remote node can't see your coins or steal them, however, the node would be able to make you see a false view of the blockchain state.

However, this seems like a nice trade off, especially if run through a mixnet, then the node will have trouble feeding it's modified state to clients, since it will be hard for it to distinguish a target.

Answer 1

Let's first start with what's needed to compute which outputs are destined for you:

• The tx public key (R)
• Each one-time output destination destination key in the tx (P)
• Your wallets private view key (a)

Therefore, a wallet either needs to offload (trust) sending their private view key to some other node which can perform the scan, or they have to have all the above locally. The remote node (in your example) cannot steal coins, as it doesn't have your private spend key, but it leaks privacy because the remote node can see how much money is sent to you (you have divulged your private view key). This latter point is the problem.