Scaling Bitcoin workshop : Tel Aviv 2019

WIP: Offline transactions

Work in progress sessions

Scaling Bitcoin 2019 Tel Aviv "yesod"

https://twitter.com/kanzure/status/1172173183329476609

Offline transactions

Daniel Marquez

Introduction

The inspiration for this work came from the concept of banking the unbanked, the open money inititaive introduced me to this, and then MIT DCI's sponsorship of the ethics course and blockchain ethics course this concept of banking the unbanked. This is a subset of that that I would like to talk about, which involves offline transactions.

Use cases

I am interested in post-natural disasters or suboptimal infrastructure. Venezuela where the infrastructure might be down but I want to buy basic necessities or maybe a hurricane goes through Miami and I want things to work while everything is offline.

Possible solutions

There are some possible solutions like the OpenDime wallet or other HSM wallets. There's layer 2 like the lightning network.

Lightning network

Why LN? It's robust, it's getting better, a lot of the talks have focused on LN. What about payment channels when parties go offline? But this doesn't fit the use case, because how can two parties instantiate offline payments?

WIP

This is very much a work in progress. Email me or tweet at me: dmarquez@mit.edu or tweet at bumangues92. The idea is to enable these transactions over WLAN or bluetooth or something.

Q: What about trusted execution environments where you prove that you deleted the private key?

A: I can't really talk about that, but I'll look into that.

Q: I don't think they have attestations. I would want a proof that you are running the hardware you're claiming you're running. We can't do ...

BB: You can do 2-of-2 multisig with the sender and the recipient and then delete the private key. But they can double spend it out from under you unfortunately. You can probably do offline transactions if you are willing to tolerate an on-chain delay of like 3 months.