Last updated September, 2016. If you read on, feel free to leave a comment about what you think. If you think I’ve missed something, please let me know that, too. 🙂

I. Introduction

What’s blockchain technology? Software. And a buzz word.

From there, it depends how you define it… 

While most of the time this term is used without definition, there’s ongoing discussion about what “blockchain technology” refers to because there are many ways to build and use a blockchain.

Technically, a blockchain is a data structure composed of blocks of information that are chained together with a cryptographic technique known as hashing (discussed in Part III, or explained here). This makes it infeasible to tamper with the data in the chain.

Conceptually, a blockchain is a shared ledger that allows participants to have a constantly updated copy of information about the transactions happening within the network of participants. It is a network and a data structure simultaneously (thank you @leashless for that point of clarity!).

Bitcoin, which is a sophisticated cryptocurrency, first brought blockchain tech into the world in 2008. Since then, new technologies based on how bitcoin works have begun to emerge.

One of my favorite parts about working in this space is that it’s complicated, which leads to awesome conversations and debates around its business and legal implications. Blockchain technology also sparks creative thinking and questioning of first principles amongst all kinds of people. And, the more you collaborate effectively, the better you can leverage the technology.

I think Antony Lewis has a great analogy about how we can define blockchain technology on his blog, Bits on Blocks.

He breaks down the tech’s main characteristics, comparing those features to legos which can be organized in different ways to get different results. This is useful because the technologies that are based on, but differ from, Bitcoin have different ways of addressing features like usability, security, and consensus.

[Consensus is agreement about the state of the network. Put simply, that is, does the network agree you have [initial balance] + $200 once your counter-party sends you a transaction, and does your counter-party end up with [their initial balance] – $200?]

If you’re looking for a more detailed technical definition, you can start by reading the original paper that explains Bitcoin, the OG blockchain. And it’s only 9 freakin’ pages. Impressive, Satoshi. (Satoshi Nakamoto is the pseudonymous person or group of people that invented Bitcoin.) Not all of the terms are still current, but I think it is worth the read. In addition, I think maintaining pseudonymity is an interesting approach to releasing a groundbreaking technology.

Nina Kilbride, Head of Legal Engineering at Eris Industries, a smart contract app platform, outlines a concise path to learning how to code with an eye towards blockchain on her excellent blog, CryptoLawyer.net.

I’ve also heard high praise for the Coursera Bitcoin class taught by Arvind Narayanan, Joseph Bonneau, Ed Felten, and Andrew Miller.

For an overview of how blockchain technology fits into the history of computing, point your pointer over to this talk by Vinay Gupta, currently of Hexayurt Capital and formerly release coordinator for the Ethereum Foundation.

Want to know how I think about blockchain technology? Keep reading here.