From a Lightning Zap to CashU

A new project that brings you Cashu any time you get a Zap to a Lightning Address

Lightning Address

It is possible to receive Lightning micropayments, simply using a Lightning Address. An address that resembles an email but allows you to receive Sats in an extremely direct way. It uses the power of LNURL technology.

A Lightning address may be created and connected to your own node. In that case you get Sats and they’ll be stored on your node as incoming payments. Otherwise you can use a custodial service like Wallet of Satoshi, Alby, Sats.mobi or others to get a Lightning address and receive funds without having the need of a running Lightning node.

Another possibility is to use hold invoices to simulate a non-custodial Lightning address behavior. Blixit and Zeus (in the recent release) both use this method. In that case fees are involved. The hold invoice method is not good for the Lightning Network and for routing nodes for many technical reasons and therefore it is not much apreciated inside the community.

Here is another solution, which has a different point of view and makes possible to receive Zap without a node, but getting eCash Cashu instead.

Project Codename: SatsContact

We introduced this project, codename “SatsContact” that makes possible to have a Lightning address without a node and receive immediately any Lightning Zap received as a eCash CashU token.

What does it mean exactly? This means that every time you receive, let’s say 1000 Sats to your Lightning address, you will get a Telegram message with a eCash token inside of the same value, that you can redeem using a Cashu wallet like eNuts for example.

Sats Contact Bot main view

Here the steps to achieve that result:

1. Go to Telegram and start chatting with @ SatsContactBot (be sure to have a telegram username specified for the Bot to work properly)

2. Hit start command

3. The Bot will show you your assigned Lightning Address and the correspondant LNURL

4. Now you are ok. To make a test, with your external wallet try sending a few Sats from 10 Sats upwards

5. After a couple of minutes, the Bot will send you a Telegram message with Cashu tokens inside.

6. Now just redeem the eCash with eNuts wallet

SatsContact Bot sending you a message with your Zap as Cashu token

Now it is very easy. Just copy from your mobile the token string and go to your eNuts Wallet, for pasting it in the redeem section. You will have the transaction appearing as the newest on top of the transactions list.

eNuts transaction view showing incoming transactions

A little bit of history of Chaumian ecash. Chaumian eCash refers to a form of digital currency designed by cryptographer David Chaum in the 1980s. It aimed to enable online cash transactions with privacy features akin to physical cash.

This eCash system utilized cryptographic techniques to ensure the anonymity of users and the security of transactions. It allowed for the creation of digital tokens that could be spent anonymously, preventing third parties from tracing transactions back to individuals.

The system involved the use of blind signatures, where a user could obtain a digital coin with a signature from the “bank”, making it possible to spend it without the “bank” being able to link the spending to the specific coin.

Cashu is an implementation of such ecash which uses Lightning as payment layer. The mint is the system which is responsible of issuing tokens and which must be reachable to redeem them and convert back to Lightning Sats.