What is npub.cash?

By StarBuilder February 26, 2024

Let’s start with definitions:

Cashu - Cashu is a free and open-source Chaumian ecash system built for Bitcoin. Cashu offers near-perfect privacy for users of custodial Bitcoin applications. Nobody needs to know who you are, how much funds you have, and who you transact with. - more info here https://cashu.space/

Cashu-adress - it is a protocol that runs on top of cashu mints. More info here: https://docs.cashu-address.com/

Npub.cash - service that runs on top of cashu-address protocol. Let’s you use your npub@npub.cash as a lightning address to receive zaps or incoming sats. More info here https://npub.cash/

Pay to public key - Like bitcoin you can cashu tokens are bearer assets and can be locked to a public key. This means only the person who has the private key can use that token.

What do you use it for? - Use your npub cash as your lightning address replacement.

Why? I believe everyone knows what a lightning address is. Lightning address is usually provided by your wallet provider who also runs their lightning node. E.g. if you have @alby.com lightning address then you already have an account setup with alby and using their lightning node to get your sats. With npub.cash you can simply put your npubaddress@npub.cash without registering first or signing up. And you can keep this forever even while changing your lightning wallet from alby to any other provider or running your own lightning node.

Npub.cash locks the received tokens into your nostr public key (Still work in progress) so that only the owner of Nostr public key who has the private key can claim the token and push it to their wallet of choice.

Benefits Over Traditional Custodial Lightning Addresses:

Privacy: With Cashu-Address, your financial activities are not visible to your custodian. This added layer of privacy ensures that your transactions remain your own.

Flexibility in Custodian Selection: Unlike traditional Lightning Addresses, Cashu-Address allows you to choose your custodian freely. If your needs change, you can switch your custodian anytime without hassle.

No User Exclusion: Custodians cannot exclude individual users. Because mints do know know which user eCash belongs to, they can not censor certain users. How to claim your username@npub.cash - This is what makes it so cool. You can actually get a vanity username for your profile name. E.g. I got mine as starbuilder@npub.cash. Simply visit npub.cash website and click the get username button. Put in your vanity username and pay 5k sats to get your profile@npub.cash

How to claim your username@npub.cash- This is what makes it so cool. You can actually get a vanity username for your profile name. E.g. I got mine as starbuilder@npub.cash. Simply visit npub.cash website and click the get username button. Put in your vanity username and pay 5k sats to get your profile@npub.cash . This is onetime and you can use this address forever..!

Frequently asked Questions:

What connect string to use to login with NIP-46 on iOS. - try setting up an account at https://use.nsec.app/home . This is still WIP. If it does not work, just try the Nostr extension using laptop browser
Is there a notification when I receive sats/zaps? Not yet. We are working on it. However, just go to npub.cash every couple of days to sweep your collected sats to your wallet
Which cashu wallet to use? Use enuts (android & ios) https://www.enuts.cash/ or minibits.cash for android https://www.minibits.cash/
Will anyone be able to claim my sats? NO. When you start the claim process you need to sign with your Nostr extenstion signer to claim sats. So only the person controlling the private key to the npub can claim sats.
I really struggle to understand the flow of what happened concretely. - Don’t break your head. the devs got you covered. Also, this is super new and everyone is trying to get their heads around. Just follow instructions, play with it and ask for help.
Is it non-custodial? - When we lock your sats to your pubkey we cannot spend it. However locking to pubkey is not enabled until wallets can start supporting them.
How do I ask for help? - just post #asknpub.cash and post your questions. We will get to you.
Who are the devs behind this? @calle (Master of Cashu) @egge (Core dev) @starbuilder (dev support)

Here’s what everyone is talking about #npub.cash on Nostr

karnage

Feb 24, 2024 13:19

In case anyone is still confused about nuts or what it means and why we always talk about it (me today haha), here is my know-nothing dummy explanation and why this is a big deal IMO:

Cashu is an ecash protocol(is this correct?) created by @calle

People are calling them nuts because cashews are nuts… get it?

The terminology is irrelevant. They can be called tokens, air, water, chicken teriyaki.. it really doesn’t matter! What matter is that this is a Layer 3 payment system that transfers tokens at the speed of light (or so I think). Lightning being layer 2, and bitcoin being layer 1.

The reason why this is a significant development is because now everyone has a cashu address. Thanks to amazing work by the legendary @Egge , if you go to npub.cash you can see that you already have an address to receive these layer 3 tokens, which just happen to be easily redeemable into lightning. This means that any new person who joins nostr automatically has (custodial) layer 3 payment access, which can swap into layer 2 and into layer 1 and into fiat if need be.

I don’t know any of the underlying mechanics of this, I am not a genius like @calle and what I have described could be incorrect, but it sure feels like this is roughly how things work.

Nuts are custodial, meaning a mint is holding your balance and can look up your npub to see if you have some. Once called upon, these nuts can be sent to another nutter (cashu wallet) or directly to a lightning address! This interoperability makes everyone a layer 2 user. All we need is a clever UX toggle / button / terminology to make it really obvious.

IF this were to be turned into a library that devs could include in their client code and “it just works”, THEN it could be a game changer! No more directing people on how to get a wallet right as they join. They can experience the magic of bitcoin indirectly via layer 3 > layer 2 transfer all without knowing anything (as long as they can get on nostr).

In practice, this means anyone joining an audio nest, a zapstream, a flare.pub can automatically get paid. Yes, it’s just tokens, and yes it’s centralized and custodial, BUT, they see the value instantly and are only a click away from digging deeper. It’s a STEPPING STONE that makes it significantly easier to get onboarded into the new paradigm.

I have not been this excited since the discovery of nostr itself! If I’m mistaken somehow, or don’t understand things correctly, please let me know and forgive my dumbass 🤣 And if this means what I think it means, then let’s make magic happen!

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retired npub

Feb 25, 2024 22:41

There’s so much technology to learn. I learn on #Nostr every single day. Today I wrapped my head around the Cashu protocol and signed up for an npub.cash address. I also created an account on the Matrix IM

In the meantime, people are making hate posts about religious strife on Facebook 😐

Some people don’t even know what a bubble is, let alone get out of it

#grownostr #plebchain

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btconboard #LNHANCE or #CTV

Feb 25, 2024 13:55

The two big benefits of ecash (what cashu uses) are privacy and scalability, of course with some trade offs - namely it is custodial.

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walker

Feb 24, 2024 22:58

Just claimed walker@npub.cash in preparation for my #BitcoinTalk with @calle on Monday 🤙🥜

Can’t wait to talk about Deez Nuts & Other Stuff Transmitted by Relays