What are people talking about when they talk about smart contracts?
In the context of blockchains and cryptocurrencies, smart contracts are:
– pre-written logic (computer code),
– stored and replicated on a distributed storage platform (eg a blockchain),
– executed/run by a network of computers (usually the same ones running the blockchain),
– and can result in ledger updates (cryptocurrency payments, etc).
… In other words, they are little programs that execute “if this happens then do that”, run and verified by many computers to ensure trustworthiness.
If blockchains give us distributed trustworthy storage, then smart contracts give us distributed trustworthy calculations.
Smart contracts are one of the functionalities that sets Ethereum apart from other blockchains.
I am often forwarded news articles of blockchain experiments run by banks or large companies, questioning “Why are they using a blockchain for this internal use-case?”.
Given that a blockchain is meant to replace a trusted external third party, or is meant to create trust between entities who don’t fully trust each other, an internal blockchain seems a contradiction in terms.
However, many of the publicly declared experiments, pilots and proof of concepts have focused on blockchains for internal use cases, ie a blockchain where there may be one or more nodes, but all under control of the same organisation, often within one department.
Although there has been much recent discussion about public (permissionless) vs private (permissioned) consortium blockchains, there has not been much debate on the virtues of internal blockchains.
Important note: If you own more than $1,000 worth of cryptocurrency then you should definitely be using a hardware wallet instead of keeping coins on exchanges. I recommend a Trezor which you can buy for €89 directly from their website.
This article is a gentle introduction to bitcoin and assumes minimal technical knowledge.
Shorter companion pieces to this are:
In the popular media, you will often read comments like “Bitcoins are stored in a digital wallet”, or “You can send money using blockchain technology”. These comments can be misleading and can confuse. By the end of this you should understand enough to participate in a dinnertime conversation about bitcoin, and not be mystified by the topic.