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The situation on the main island of Cuba grows more difficult by the day due to the "alumbrones" (flickers of power) — a term used because a "blackout" would imply 4 hours without electricity, whereas in Cuba, it’s 2 hours with electricity. Adding to this, internet connectivity, already unreliable, worsens due to the lack of power.
Despite this, the Cuba Bitcoin Community has worked hard to establish a Lightning node, using an LNbits instance that provides a custodial solution where custody is managed by the community itself. They also offer their own BTCpay Server instance, tailored to merchants’ needs with the most practical solutions for local conditions.
We are now exploring solutions that can function during OFFLINE periods. Cashu has emerged as a potential option, which is why we’ve been researching it. We could implement a Fedimint with a 1:1 parity to satoshis (sats), allowing users to hold eCash (Cashu) — akin to a "check" obtained offline that can be "cashed" once internet access is restored.
I’d like to hear your thoughts on this approach and any suggestions to improve it or alternative solutions. All feedback is welcome. Friend @DarthCoin, what do you think?
ESPAÑOL
Podría ser eCash(Cashu) una solución apropiada para Cuba?
Cada día es más difícil la situación en la Isla grande de Cuba por los "alumbrones" ya que apagón sería si tuvieras 4 SIN corriente eléctrica, en Cuba son 2 horas CON corriente eléctrica. Suma a esto que la conexión a internet, ya mala en su funcionamiento, empeora a causa de estar sin corriente eléctrica. Aún así la Comunidad Cuba Bitcoin se ha esforzado por de alguna manera tener un nodo Lightning, con una instancia LNbits que permite a los usuarios tener una solución custodial, pero donde la custodia es ofrecida por la propia comunidad, además también se ofrece una instancia de BTCpay Server propia, con las soluciones más convenientes para los comerciantes según las necesidades de aquí.
Ahora estamos pensando en proveer de alguna solución que pueda funcionar en los momentos que estamos OFFLINE. Se presenta Cashu como esa solución, por lo que hemos ido investigando. Podríamos tener una Fedimint, con una paridad 1:1 con SAT y así el usuario tendría la posibilidad de tener su eCash (Cashu), que sería como un cheque obtenido mientras estaba offline y en el momento que tiene acceso a la conexión pues cobra su cheque.
Me gustaría saber cómo ven esta solución y si existiría alguna sugerencia que pudiera mejorarla u otra solución diferente. Todos los comentarios son muy bienvenidos. Amigo @DarthCoin qué piensas?
cashu has a relatively new feature, that allows for partial offline payments. In general, all ecash payments can be done offline, since all it is is giving the ecash stored on one device to another device.
BUT, if you rely on only this for offline payments, there is a possibility for the sender to front run the receiver, and thus revert the payment.
This is because ecash notes are made of something called a secret and a sinature. If a person has both of these, they can spend the ecash. So as the receiver, you always have to make sure that you exchange secrets that are known by the sender, for new secrets that only you know. We call this a swap.
Regarding offline payments, as the sender, it is really simple. You don't need to be online, as long as you have the exact amount in coins you are trying to send. Then you can simply give the coins to the receiver.
For the receiver however, the problem we discussed above applies. There is a solution for this, made of two components. It does however require the sender to be online, because he needs to create custom notes at the mint (swap).
The technique for offline receive uses ecash with a lock to the receiver, and a offline verifiable signature. If an ecash note has both these components, the receiver can be confident that the sender cannot revert the transaction.
It is possible to create fully offline transactions, if you are able to lock ecash to the recipient in advance (while online). In this case, you usually need to have an additional refund spending condition with a timelock, that lets you get your unspent ecash back after the expiry. This is because you might know in advanve who you will be spending to, but maybe not the exact amount.
This is a simplified explanation, I left some things out. I might write an article on thia topic, i think there is a lot of interest around it.
https://snf2025.gandlaf.com/#/22 here is a small graphic for understanding
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Thank you very much for your contribution. We are currently in the research and development phase of the solution, which is why we are seeking any help possible.
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some more info on the topic!
cheers!
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Keep n mind the "diversification" approach. Don't rely on in one single solution. You are doing great already, considering all the adversities your community is facing. Offering cashu to your community is a great addition to the toolkit you have already setup. Onchain savings, LN daily spending, BTCpay for merchant and Cashu for adverse situations: you are way forward 1% of other people worldwide. Great point, is that you are using it, not just learning about it. Keep it up hermano!
Leet people know these options are available and help them learn about it and how to use them in the daily life. Cashu come with embedded trust (same as Fedimint) so receiver always need a way to go back to the sender and tell something when wrong redeeming the ecash.
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161 sats \ 2 replies \ @ek 13 Apr
Cashu has emerged as a potential option, which is why we’ve been researching it. We could implement a Fedimint with a 1:1 parity to satoshis (sats), allowing users to hold eCash (Cashu)
This sounds like you’re mixing Fedimint and Cashu but Fedimint and Cashu are two completely separate protocols for ecash. Since they are not compatible with each other, you need to decide if you want to use Fedimint or Cashu but using both doesn’t make sense.
As a community, you probably want to look into Fedimint but I’m not aware of any Fedimint wallet while there are plenty for Cashu.
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Do you mean this ? 🫣
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You're right. I should have actually mentioned Fedimint or Cashu. My mistake. We are exploring all possible solutions to help the majority. Thank you for the correction.
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I think you already got good answers here, I have nothing to add. I commented just to see that I read your post.
The only thing I could add is to create your own community cashu mint. That will more trust. Keep fighting for freedom!
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Gracias. Siempre apreciamos tus recomendaciones. Realmente han sido de mucha ayuda todos los comentarios. En realidad lo que estamos estructurando es que sea la nuestra comunidad quien custodie los fondos. De alguna manera lo hacemos usando LNbits, ahora necesitamos una solución Anti-apagones y que permita transferir valor incluso sin conexión y creemos que esta es la vía.
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Asi es, estas en el buen camino en tu caso muy especial. Creo que los cubanos tienen el caso mas especial de como usar Bitcoin.
  • crear tu proprio cashu mint, para la comunidad
  • usar ecash offline entre vosotros y hacer que crezca la economia circular
  • usar la salida del ecash por LN solamente cuando necesitas hacer pagos en el exterior de la comunidad. Para esto si que se necesita un nodo LN con buena liquidez y conexiones con otros nodos.
NOTA: en caso si alguien utiliza un mint fuera de la comunidad, no te olvides de consultar esta pagina de los mints, es una auditoria: https://audit.8333.space/
De alguna manera lo hacemos usando LNbits
Lamentable... LNbits ya no tiene la extension de cashu. Tienes que usar otras herramientas para manejar el mint.
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Sí ya hemos estado revisando esa información de la auditoría. Lo del nodo Lightning ya lo tenemos, está bastante bien conectado. Nos va quedando lo del minteo y la manera correcta de usar offline esta solución. Pero le vamos metiendo poco a poco. Te agradecemos nuevamente tus aportes
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Como ya tienes una instancia de LNbits era muy facil de arrancar el mint con la extension de cashu. Tal como lo he describido en mi guia: https://darth-coin.github.io/wallets/bitcoin-adoption-using-ecash-es.html
Pero es lamentable que @calle ya no mantiene esta extension https://github.com/lnbits/cashu para lnbits. Ahora tienes que usar nutshell https://github.com/cashubtc/nutshell
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I'm on another island also looking into cashu as a solution to the outage issue (though its not as bad here). I've been preparing a workshop to get people to bring up their own lnbits nodes. I'm teaching a class end of this month - will report on progress.
However... Over here I'm fighting get-rich-quick-schemes on the daily, narrating that no, USDT is not gonna make you rich especially not if you send it to someone promising you returns, and no one don't need to use Tron despite half the caricom defaulting that cuz Justin bought him some Dominica officials. Its feeling like an uphill battle here 😕
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Keep doing everything possible for the right adoption. It is truly difficult to fight against years of fiat slavery, especially when the enslaved still believe the form of slavery is good and what could liberate them is evil. Thank you for sharing your vision.
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This comment has got nothing to do CASHU but I strongly believe that someone in Cuba needs to be reminded that "Each morning we are born again and What we do today is what matters most." A blissful day to you all, keep staying strong.
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Bot, right?
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Vamos a seguir dando guerra desde donde estamos y con lo que tenemos. Gracias
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STFU shitcoiner
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What's up with you and shitcoining? @DarthCoin. Is that your favorite crypto term? 🤔
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