The cryptocurrency Bitcoin has risen into public consciousness over the past few years. It is the first digital currency to reach this level of success and notoriety. Bitcoin is based on a decades old cryptographic concept called a blockchain. As people and companies seek new ways to conduct elections that make better sense in our high tech world, several startups have proposed using blockchains, or even Bitcoin itself, to conduct elections.

Using Bitcoin (or a blockchain) as an election system is a bad idea that really doesn’t make sense. While blockchains can be useful in the election process, they are only appropriate for use in one small part of a larger election system.

What is a blockchain?

A blockchain is basically a public database of information that is distributed across many different computers so that all users are able to verify that they have the same overall data even if some of the computers go down. There is no need to trust a central server or authority. A blockchain is a fundamental concept in cryptography that existed for decades prior to being used in cryptocurrencies like Bitcoin.

Blockchains are basically a chain of things (transactions in the case of Bitcoin or other cryptocurrencies, or votes in the case of elections) that gets assembled in a way that guarantees the overall integrity of everything that has been stuck together. Imagine that each transaction contained within a blockchain is stamped by a notary when the transaction occurs, and that this stamp contains key information about the transaction and its relationship to the overall chain. A cryptographic/mathematical process is applied each time some new thing is added, using this information, that verifies the overall integrity of the chain. There is a straightforward process for determining that none of the things (blocks) that have been previously added have been changed.

A blockchain is distributed across many computers, and everyone can see what it contains and determine if any of the previously added blocks have been manipulated. Therefore, if a person comes along and says the chain really looks like THIS, when everyone else says it looks like THAT, then that person is wrong and their version of the blockchain is refuted.

Using blockchains for voting has been considered by academics for decades, but only as a thought experiment. If you ask any cryptographer who knows the basics of cryptocurrencies (remember, blockchains were invented by cryptographers) if elections should be conducted using blockchains, they would laugh and say, “Hell no, that doesn’t even make sense!” While blockchains are great at securely storing information, they do literally nothing to solve the many, many challenges that elections face, like the necessity for voter anonymity, the ability to determine that only eligible voters cast votes, that only legal votes are tabulated, and that ballots and ballot boxes cannot be manipulated by anyone, etc… and the list goes on. Blockchains do nothing to address any of these critical issues.

How would Bitcoin theoretically be used for voting?

The idea is basically to give every eligible voter a very small fraction of a Bitcoin that they would ‘spend’ on a particular candidate in a particular race on Election Day. All the votes would be added to the Bitcoin blockchain, so it would contain the election results in a secure and publicly verifiable way. There are two problems with this. First, as discussed above, storing votes in a blockchain does nothing to address other security and process concerns surrounding elections. And second, because Bitcoin’s blockchain is by its very nature a public ledger, it would be impossible to maintain voter anonymity and to keep voters from proving how they voted, both of which are fundamental tenets of elections in the United States.
You can think of a blockchain as being a way to keep a ledger of information that has integrity, but not necessarily security.  In the case of Bitcoin, that information is by nature public, which wouldn’t work for elections. If you were to create a private blockchain distributed across many trusted computers it would be a great way to store cast ballots or election logs. However, secure storage for ballots and logs is only one tiny piece of the overall election puzzle. Blockchains are a good solution to this one piece, but not to “running elections” in general as some claim.