Past Meetup

Talk: How to Double Spend, Project: Crypto-Lightning ATM

This Meetup is past

6 people went

Paralelni Polis

Dělnická 43 · Prague

How to find us

We will be in the hackerspace in the basement - towards the front of the building.

Location image of event venue


This week will be a short talk about how to double-spend in Bitcoin. We will discuss the technical details behind double-spending, how practical it is, and how to mitigate the risk of double-spend attacks.

After the talk we will research and hack on our latest project: A Cryptocurrency-to-Lightning ATM. We will start with a simple proof-of-concept (script or web page) to show that it is possible. Resources for this project:


Charles is a cryptocurrency enthusiast, programmer, and entrepreneur. He has many years of professional experience developing mobile and web applications while working for start-ups in Europe as well as the United States. He is a long-time open-source contributor and for the past year he has been working full-time developing cryptocurrency payment systems.


This event is part of an ongoing series where we learn together by researching and hacking on new technologies. If you're interested in learning how professional programmers work on real projects, this is the event for you.

You can find our projects in our group's GitHub page:

We will be meeting at Paralelni Polis, an alternative cafe which hosts many different events relating to creativity and technology. The event will be in the "Hackerspace" which is located in the basement below the cafe. If you have trouble finding us, just ask around - someone will know about us.