Proof of Attendance at the MIT Bitcoin Expo

Written by Hugo Uvegi and Manasi Vora

We have come a long way since we first announced the Expo. The team has put in a lot of hard work and we are happy how the Expo is shaping up. But we are not done yet. With less than a day left for the Expo, we have an exciting announcement to share!

As we hinted at in our introductory blog post (remember the spoiler alert?), we’re going to be airdropping some satoshis (sats)! What better way to celebrate the 10th anniversary of bitcoin than by providing OGs with a few extra sats and helping new friends with their first transaction.

We wanted to do this in a technically interesting way, so in that spirit, we’re going to attempt a batch transaction to all Expo attendees for 150,000 satoshis per person.

100,000,000 sats = 1 btc (1 satoshi is the smallest unit of account in bitcoin)

All you need is a QR code

  1. If you already have a bitcoin wallet: Awesome! Bring the QR code of your address (skip Steps)
  2. If you don’t yet have a bitcoin wallet: Awesome! This is the time to get one


a. The easiest path forward is to use a mobile wallet. This site provides some good options:

b. Make sure to backup your recovery phrase, as this is the key to your wallet! Without it, you won’t be able to recover your funds if you lose your phone, etc. While this might not be a huge deal for 150,000 sats, you want to form good habits from the get go

c. Every wallet application will have some way to receive funds, whether that’s labeled as “Receive,” “Request,” or some other alternative depends on the app. Make sure you’re familiar with how to get a QR code (corresponding to an address) on the screen, so that we can make this as seamless an experience as possible

Note — If you’d like to run a full node at home, carpe diem! Head over to, download the latest version of Bitcoin Core, and when you run it, it will automatically start downloading the whole chain. That being said, this process can often take a few days depending on your hardware and bandwidth, and can require > 250 GB of free hard drive space to run an archival node. It’s a little late to start this process now, but it gives you a sense of the network that you just don’t get with mobile wallets. Jameson Lopp has a great list of resources for anyone looking to learn more:

At registration is where all the magic begins

  1. While checking in Saturday morning, you’ll provide us with a QR code to be scanned
  2. We’ll be checking people in for the airdrop from 8 am — 11 am Saturday morning (make sure to get in by then!)
  3. After 11 am, we’ll add all of these addresses to a single batch transaction on-chain! If this works correctly, this means that everyone will receive 150,000 sats in one big, joint transaction. Pretty cool, no?

What’s the point of an airdrop you ask?

Well this one is multi-faceted.

Proof of attendance:

In Bitcoin Core, you can sign a message with an address. You can then validate that message given the signature and the address. Therefore, given the payout transaction ID, you can prove you own the address the airdrop was paid to, which in turn proves you attended the MIT Bitcoin Expo 2019!


More often than not, people let their airdropped coins sit in their wallet, never to be used again. It’s a fun experience, but it doesn’t really get people using the money. This is where the opportunity for a second transaction comes in.

The After Party

Who doesn’t like an after party? To make it better, who doesn’t like a Bitcoin powered after party?

We’ll be having a quasi-official party at The Park at 10 pm Saturday. (Remember it is daylight savings night, and you don’t want to miss Peter Todd and Jamiel Sheikh debate Permissioned vs Permissionless systems Sunday morning!)

Saturday afternoon from 2 pm — 5 pm, we’ll be giving away 200 tickets for the after party. Since space is limited, these tickets will ensure you get to attend.

But here is the fun part.

In order to receive one of these tickets, you’ll have to donate (at least) 50,000 sats to an address provided at the registration tables. It is a win-win-win! You get to go to an awesome after party, make some Bitcoin transactions and be part of a good cause. Much wow!

All funds will then be donated to Code to Inspire (, a non-profit organization located in Afghanistan which seeks to empower Afghani women by teaching them to code.

We can’t wait to come experiment with you all, and have this be the first provably-attended conference! Come be part of this!

PS: We’re lucky enough to be working with a partner who will be fronting the Bitcoin