“Blockchain is a solution looking for a problem. Unless you want to buy drugs on the internet,” said the instructor in a technology training I recently attended.
While not the first time I had heard such a comment, it was disturbing that a hundred of my fellow practitioners were being misled. Ignoring or dismissing blockchain does the accounting profession no favors. Instead, let’s consider the problem that the technology solves. This will provide a basis for later understanding possible applications to our work.
What is the problem blockchain is trying to solve?
Blockchain, or distributed ledger technology, set out to solve how we transfer a digital asset between two peers without an intermediary. While there are many applications of this transfer, let’s look at it in the context of money.
Imagine you are selling a bike online. You don’t actually know the person who is buying your bike, so you have no way of knowing if the buyer actually has the money to pay for it. You have to trust an intermediary like PayPal for this information. PayPal is crucial to the transaction because it verifies what you cannot – whether the buyer has enough money in their bank account to make the purchase.
The asymmetry of trust in this transaction is known as the Byzantine General’s Problem. Imagine we have four generals planning to attack a city. At least three of the generals must attack at the same time to overpower the army holding the city. However, the only way they can communicate with each other is via messenger, and they do not know if one of the generals is a traitor. If a general were traitorous, he could modify the attack message and cause the other generals to fail. The only way to overcome a traitorous general is to provide the history of all messages sent and evidence they have not been altered. If the generals see that one of their peers has sent a message different from the others, they would know the general is traitorous and disregard his message. If more generals are good actors than bad in this attack, the correct message will be obvious.