Nostr Web Client

gandlaf21 10mo ago

#### How to run an offline fiat-bitcoin (withdraw bitcoin) ATM:

💵 ➡️ 🏧 ➡️ 🥜 ➡️ ⚡

1. Run a cashu mint

2. Mint a bunch of ecash tokens

3. Load the ecash into ATM

4. User comes, puts in 20$ cash

5. ATM displays QR code with ecash worth 20$

6. User scans token, and redeems to lightning

7. ???

8. Profit

#### How to run an offline bitcoin-fiat (withdraw fiat) ATM:

⚡➡️ 🥜 ➡️ 🏧 ➡️ 💵

1. Run a cashu mint

2. Fill ATM with cash

3. User inputs amount he wants to withdraw (20$)

4. ATM displays lock-pubkey

5. User creates offline-verifiable-locked-to-pubkey ecash QR code worth 20$

6. ATM scans QR and verifies ecash locally

7. If everything checks out, ATM dispenses 20$ cash

8. ???

9. Profit

Yes, you can combine these, but there would be limits. The ATM would need to come online to redeem locked ecash for generic ecash, in order to be able to dispense it again.

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Discussion

GameBoyBTC 10mo ago

👀‼️

nostr:note1hde5ykne3d39aq43grnjeeschajpnejjuvzaqzp8c3s27qyvyreqdhzewm

Brunswick 10mo ago

Stablesats could also be useful for this

gandlaf21 10mo ago

Yes. Ecash needs to be denominated in the fiat currency. Exchange rate ia applied when swapping to or from sats, which would happen on the users phone

43d140f6... 10mo ago

This will have extravagant outcomes... like thieves minting 500x the tokens that are actually backed by the Btc's.... any solution in sight for that "small" problem? 🧐

gandlaf21 10mo ago

yes, don't use the thieves' mint

43d140f6... 10mo ago

that's a non-solution for the actual real world...

gandlaf21 10mo ago

Ecash is a transactional medium, and is not meant to be held in large quantities. Above example shows how it enables offline exchange/ATMs. If you're running the ATM you own the mint and have no inflation risk. If you're a user, the risk is that they rug your transaction. The same risk applies for every other exchange, except maybe for atomic cross-chain swaps.

43d140f6... 10mo ago

Hmmmm.... sounds reasonable, and I'm actually a very big fan of your offline-ATM proposal 💪 I'm kind of writing those half-trolling questions to help spread knowledge about what's to be expected. Keep it up!