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Tim Bouma 6mo ago

I did it!

I can now issue a record (credential) to a NFC tag associated with a #nostr #safebox.

So I've proven I can have a fully functional wallet with only a NFC tag.

I can:

1. Pay to NFC Tag

2. Pay from NFC Tag

3. Present a record (i.e., prove) using a NFC Tag

4. Accept a Record using a NFC Tag.

and of course,

5. Login with a NFC Tag.

IMHO, this is BIG! It's now possible to have a wallet that exists independently of a phone, and which can be used with a super cheap NFC Tag.

Onward!

https://video.nostr.build/af0fcb97d28f770f72597039a937deccb7b313e3e8de8becd0e58e89122fbf25.mp4

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Discussion

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ricky 6mo ago

Where's the best place to get NFC tags?

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Tim Bouma 6mo ago

Amazon

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ricky 6mo ago

Ntag216 or 213 or…

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Jaret 6mo ago

Amazing. What’s next? This is huge.

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mfostr 6mo ago

It’s definitely big, I can envision an offline Verifiable Credential similar to an OpenPGP DID via a presentation exchange.

https://gnupg.org/ftp/specs/OpenPGP-smart-card-application-3.4.1.pdf

https://identity.foundation/presentation-exchange/

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Tim Bouma 6mo ago

I'm totally familiar with presentation exchange protocols and decided to build everything from the ground up with nostr. Also card security - keeping all of the encryption and logic in the application versus the card actually makes things more secure. I also replicated the things I liked from the tokenized card payment system (Visa, Mastercard). The best thing about nostr is that I did not have to ask for permission to do what I am doing. I just built what I wanted.

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mfostr 6mo ago

I absolutely love it, I would like to check it out. Are you going to open source it? Does it require an invite?

What make/version NFC tag/card, and size do you recommend? I ran into limitations with NTAG215 tags only being 504 bytes.

I did notice you wrote a urn:vwi spec similar to a DID. Nostr is great because of the permission-less capabilities you mentioned. We actually have a chance of fliping the internet right side up again. 👏

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Crusty 👨‍💻 6mo ago

This uses "someone elses node", right?

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Big Barry Bitcoin 6mo ago

How do you decide how much to spend? Does the NFC tag only reveal as much as minimally needed?

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Tim Bouma 6mo ago

I encode a default tip amount (21 sats) if no amount is specified by the acquiring app. The info is encrypted and can only be decrypted by the vault that did the issuance. Also, the vault needed to ‘trust’ the acquiring instance (known public key) before it does anything.