What’s the difference between a distributed ledger and a blockchain?

A blockchain is a type of distributed ledger.  But new distributed ledgers are emerging. These are databases where control over the data’s evolution is shared between entities. Here’s a handy cheatsheet.

Continue reading

The emergence of blockchains as Activity Registers

This post tries to describe two very different uses for blockchain technology: Digital Token Ledgers that record ownership changes of digital tokens, and Activity Registers that record timestamped proofs of existence of data or agreements about data.  Bitcoin is used for both.

Continue reading

No, “Blockchain” is not a solution looking for a problem

I have heard this comment many times:

“Blockchain” is a solution looking for a problem.


That is incorrect – here’s the problem statement, originally articulated in 2008:
Bitcoin whitepaper

The problem statement, to paraphrase, is

“How do people pay each other electronically without being at the behest of Financial Institutions?”

The proposed solution is:


Continue reading

Confused by blockchains? Revolution vs Evolution

Confused by blockchains? Revolution vs Evolution

This article attempts to explain the difference between the revolutionary disruptive innovation of bitcoin and the evolutionary efficiency innovations of industry workflow tools, and why calling them both “blockchains”, even as a generic term, is incredibly confusing.
Cryptocurrencies vs Industry Workflow Tools

For the rest of this post, I will use the phrase “industry workflow tools” instead of industry blockchains, as some of the emerging solutions being proposed in this space are not blockchains (eg, R3’s Corda is not a blockchain but Digital Asset’s solutions are – however, both companies are proposing industry workflow tools).

Continue reading

Bitcoin’s network in one infographic

I have been looking for a one pager explaining the difference between users, miners, nodes and other participants on the bitcoin network.  I couldn’t find one so I attempted to draw my own.  Here it is.

Click on the image for a high-resolution copy you can download, share, copy and print.

Feedback very welcome!

Bitcoin's network

Bitcoin’s network

In a nutshell: MultiChain (Epicenter Bitcoin interview – Nov 2015)

In a nutshell: MultiChain (Epicenter Bitcoin interview – Nov 2015)

I enjoyed listening to episode 107 of the podcast “Epicenter Bitcoin” where Gideon Greenspan, CEO and Founder of Coin Sciences was interviewed about MultiChain. Gideon also writes a great blog. Here are my notes on parts of the podcast that I found particularly interesting. Misunderstandings and paraphrasing errors are mine.

Note: The term ‘miner’ is used frequently in the podcast but I try to refer to them here as block-makers or block-adders.

This gets fairly technical; if this is hard to follow, it may be helpful to read my introductions to blockchains, bitcoin, digital tokens, and smart contracts first.

Continue reading

A gentle introduction to immutability of blockchains

In the context of data security, the immutability of data stored on blockchains is important. What do people mean when they say “Blockchains are immutable”? In this post I try to explain the key concepts.

It may be useful to read introductions to blockchains and Bitcoin if you have just arrived here or are unfamiliar with them.

Continue reading