Is there any work being done on private #cashu mints?
I'd love to have something I can setup in my LN node and then give an invite code out to 5-10 friends
Seems like an easy way to onboard family to lightning without too much downside
Discussion
With private you mean personal? Afaik mints doesn't have any kind of announcement mechanism so you can create your one with the existing mints solution that exist and share it just with your people. No other one will known the mint url
That works for setting it up, but as soon as they send a cashu token the mint URL will be spread :(
so it should travel only inside encrypted direct messages then
Yes, that's true. The solution can feel quite complicated, particularly when it comes to whitelisting or blacklisting users, which is impossible due to the nature of blind signatures and e-cash. However, perhaps the solution lies in a similar direction: a middleware that utilizes blindly emmited certificates to authenticate interactions with the mint. These certificates would be issued as blind-signed notes by the mint, functioning as bearer tokens to authenticate interactions with the mint. Does this make sense, or is it a bit convoluted?
Perhaps the certificates could have an expiration time, allowing them to be used multiple times. In this scenario, the user would simply need to renew them within a defined period of time.
We could use ring signatures as access right authentication.
Each of your friends exchange pubkeys with you and each other, then you require an additional ring signature with each ecash transfer.
Meaning only your friends can transact the ecash among themselves, but nobody else can spend the ecash tokens.
Yet still there is perfect privacy among the tokens of your friends.
I don't know how I could integrate the ring signatures into an existing app. But you bring up an interesting point.
I think I would only need to restrict minting token from lightning ( in bound liquidity )
Outbound liquidity could be public, that way if my friends sent the tokens to a stranger they could swap out to LN
Yes! We're going to have a generalized blind auth scheme so you can share an invite code or limit who can create an account with your friends for example while they can still enjoy privacy within the anon set of your mint.
This is a bigger project though, likely will take some time but we already started.
imagine
even public cashu mints and apps don't work already, this will so not work it will be crazy, revolutionary
More info here https://github.com/cashubtc/nuts/pull/106