Thanks @gbks for bringing up the topic on the Bitcoin.Design community

Cashu is a free and open-source chaumian ecash system that offers near-perfect privacy for users of custodial Bitcoin applications. One of the benefits of it is that nobody will know who you are, how much funds you have, and who you transact with.

The protocol is deeply integrated with the Lightning Network that function as a bridge between your sats and the ecash tokens that it generates. Cashu wallets can be easily used as regular Bitcoin Lightning wallets but with the added benefit of nearly perfect privacy given buy the fact that mints run as a centralized entity orchestrating and providing the tokens. While you hodl the token, the mints will hodl the sats as collateral until the token is redeem back.

We have already seen many ecash-dedicated-wallets¹ landing to the space, using different mint's Lightning nodes for sending and receiving sats payments anonymously in exchange for ecash. The inverse could also happen: existing Lightning wallets implementing cashu as an additional layer for anonymity.

I wanted to play with it and simulate a possible integration into Blue Wallet² (that currently does not support Cashu). Below is a breakdown of how a potential screens flow could enable the user to create not only an onchain wallet and a Lighting wallet, but also a cashu wallet to send and receive nuts. Here below the steps:

Just to be clear, this is just a hypothetical example and Cashu integration is not currently available in Blue Wallet. I'm not considering any technicalities when designing this flows, and am totally unaware how much effort implement something like this it could take. I believe that adding Cashu to existing Bitcoin mobile wallets presents a unique opportunity to improve user privacy and transaction efficiency over Lightning.

Funding the Cashu wallet hitting "Manage Finds" could work the same way it already does when clicking the same button to fund a Lightning wallet with onchain assets. I'd like to know what you think about this? It's worth the effort? You'd see cashu integrated on other common Lighting wallets WoS, Phoenix or Blixt?

Any feedback or suggestion will be much appreciated.