---
layout: static-informational
title: Adam Back
description: "90s Cypherpunk, Inventor of HashCash, CEO of Blockstream"
permalink: /people/adam-back
people-groups: []
---

From wikipedia:

> Adam Back (born July 1970) is a British cryptographer and crypto-hacker.

> He is the inventor of hashcash, the proof-of-work system used by several anti-spam systems. A similar system is used in bitcoin. Hashcash has also been used in a number of other protocols such as combating blog spam, and defending against user namespace pollution.

> He is also known for pioneering the use of ultra-compact code with his 3-line RSA in Perl signature file and non-exportable T-shirts to protest the (now relaxed) United States cryptography export regulations.

> Today he is CEO of Blockstream, a company that seeks to further the development of bitcoin and blockchain technology.

## Links

* [Adam Back on Wikipedia](https://en.wikipedia.org/wiki/Adam_Back)
* [@adam3us on Twitter](https://twitter.com/adam3us)
* [Hashcash on Wikipedia](https://en.wikipedia.org/wiki/Hashcash)
* [hashcash.org](http://www.hashcash.org/)
* [Hashcash white paper](http://www.hashcash.org/papers/hashcash.pdf) - _[mirror](http://nakamotoinstitute.org/static/docs/hashcash.pdf)_
* [Blockstream on Wikipedia](https://en.wikipedia.org/wiki/Blockstream)
* [Blockstream.com](https://blockstream.com/)
* 03-Feb-2015 Epicenter Bitcoin on Youtube - [EB65 – Adam Back & Greg Maxwell: Sidechains Unchained](https://www.youtube.com/watch?v=jE_elgnIw3M) with [Gregory Maxwell](/people/gregory_maxwell.md)
* 07-Sep-2015 Epicenter Bitcoin on Youtube - [EB95 – Adam Back: Why Bitcoin Needs A Measured Approach To Scaling](https://www.youtube.com/watch?v=wYHyR2E5Pic)
* 09-Oct-2016 Kristov Atlas on Youtube - [Fungibility Overview by Adam Back and Matt Corallo (Scaling Bitcoin Milan 2016)](https://www.youtube.com/watch?v=AvS3tp0qqgA) with [Matt Corallo](/people/matt_corallo.md)
* 17-Mar-2017 Medium.com - [Adam Back and Greg Maxwell aren’t the kings of Bitcoin](https://medium.com/@Chris_Stewart_5/adam-back-and-greg-maxwell-arent-the-kings-of-bitcoin-9e03e0a52177) by Chris Stewart