Show HN: Paypyrus – Electronic money in physical form with Venmo | Hacker News Reader

Show HN: Paypyrus – Electronic money in physical form with Venmo

github.com

25 pointscydrobolt16 comments

So I only see two major downsides: 1) I basically I have to verify/transact every "printed" money the moment I get it - preferably using a smartphone - in case someone else has a copy of it and "takes" it first. Copies could be made with any high-resolution camera. 2) If the money travels from A to B to C in paper shape and the digital transaction will be from A to C then A will know that B has done business with C.

Unless the note changes hands additional times between B and C.

Point taken. It then just becomes a statistical probability of how many steps between A and N. Considering that everybody using this system better have 0 steps (former point made) 1 step is about the furthest I would hope. But you are right: there could be more steps.

Yeah. Right now, it is largely based on trust. We're hoping to implement some kind of one-time "seal" and new token that a user can verify after receiving a bill to ensure that someone else can't activate it with a picture or by saving the token. That obviously comes with the downside of making it more difficult to transfer.

As a proof of concept, and being based on Venmo, I think it is and will be largely based on user trust as long as the bill creator keeps the funds (Venmo allows no bot accounts).

It is unclear from description (and I am too lazy to read the code) how it works.

The first question is whether such paper "bill" would guarantee payment. Could issuer refuse to pay it, when presented. In other words such paper bill is analogous to dollar bill or bank check? If this feature could not be implemented with Venmo API, perhaps one can build some kind of escrow service.

My second question is about privacy. Is identity of the original paper bill "issuer" is disclosed to recipient?

https://github.com/cydrobolt/paypyrus/blob/master/pp/models....

looks like it's web app that holds transactions and sends them to venmo when redeemed

It would be similar to a cheque, central banks and governments do not like normal people printing "money" or inventing their own

a better alternative would be bitcoin paperwallets, this here relies on Venmo to play nice as well as the "payer"

Agreed. Using Bitcoin would definitely help make it resemble cash, however, this could potentially be less convenient. Venmo is more popular among students, especially on university campuses, so the idea was to make it easy to adopt among friend groups, not specifically to guarantee the transfer of funds.

Paypyrus being based on Venmo, we cannot guarantee payment if the bill creator decides to revoke our authorisation or delete the bill. This is due to Venmo's friend-to-friend model, which we are based on. No bot accounts are allowed, so the money is never placed in our hands. It is a direct P2P payment between friends, presumably.

This would be analogous to a bank check rather than a paper bill. Since it is not legal tender and there is no middleman in the transaction, it could not be spent (or stolen) as easily as a dollar bill.

I actually made something pretty similar to this for Bitcoin. Basically printed coins with the public key on the outside and the private key inside, so you could verify that the "wallet" was full and then break it open once you're ready to redeem.

In practice, it was only really useful as a gimmick/fun tool for giving people their first bitcoin.

>Paypyrus is versatile like cash

But with none of the security, what a useful idea... Could I not just print the same dollar twenty times then it's a race to see who redeems it first? Cute idea though I guess.

I think that they can add security features in the future.

  $ cat /var/history.log | grep 'add.*security.*future' | grep -v failure | wc -l
  0

Agreed. Although it has none of the guarantees of cash, it would also be more difficult to steal (as the authorization can be revoked). This is more similar to a bank check than actual legal tender.

(potential drunken party game: throw 10 paypyruses and the first to cash in gets the money)

This is a hell of an idea. Haha, Damn you this has triggered my entrepreneurial ADD, it makes me want to build something around it! Venmo should not ignore this. They could really build upon this, and get some vendor lock-in if it gains popularity among their already loyal users.

This is just like printing out private keys for bitcoin wallet. AKA "paper wallet".

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