Usage of the word “blockchain”

I dug into the history of the term blockchain. As a former technical writer, it’s hard not to cringe when I see yet another ambiguous use of this word.

Here I will relate my research into the history of the word blockchain, and a few opinions on it’s usage. If you are interested in the history of this term, or if you just want to avoid confusing people when you use it, you might want to give this a read.


Cipher Block Chaining: 1976 — This technique didn’t coin the word, but it’s the oldest construct I can find that is somewhat similar. Cypher block chaining does not utilize an event stream — a feature of all blockchains — so it’s a stretch to say that this is a precuror to modern usage of the word blockchain— but Cipher Block Chaining may have influenced the terminology of Satoshi, who(m) was(were) probably familiar with it.

Cryptography mailing list: Late 1997 — Discussions of HashCash use the phrase “block chain” to talk about an event stream of blocks using digital signatures. This is sort of close to what we want, because HashCash used a PoW concept, arguably as a consensus mechanism. The emails on this list the first uses I have found of the phrase “block chain” in a similar manner to modern usage.

The bitcoin whitepaper: Early 2008 — This paper didn’t coin the word — it refers to a blockchain as “chain of blocks” and a token as a “chain of digital signatures”. However, the bitcoin whitepaper defined common usage of blockchains and the characteristics of blockchain data structures. Obviously, this work was underway (probably highly collaboratively) long before it was released.

Cryptography mailing list: Late 2008 — Hal Finney starts to use “block chain” (two words) to refer to the data structure Satoshi described. I’m having trouble finding earlier uses on that particular mailing list, but I suspect they exist.

Some historic sites:

History of bitcoin : A neat timeline website with some important events in the history of bitcoin.

Satoshi Nakamoto Institute: A little history from the cypherpunks list and a lot of other fun stuff here.

Molebit was an early adopter and has some history.

Archives of the metzdowd mailing list on which Satoshi announced bitcoin.

Opinion: How to use the word “blockchain” with clarity:

There are only three uses of the work blockchain that I have found to be clear and common in academic literature (A, B, and C below).

An end run is…define your terms! If you have an innovative use of the term blockchain, define it up front, during or before it’s first use in your writing. You will find an example of that below as well.

A) blockchain (n.):

(1) (data structure) A decentralized database, usually featuring consensus on write, and constructed as an event stream of “blocks”. Dictionaries will offer some form of this definition. i.e. “That data is on the blockchain.”

(2) (data structure plus algorithms) The set of rules set forth for using an instance a data structure as in 1. i.e. “That blockchain does not support Proof of Stake, yet.”

(3) (network) The network of nodes running an instance as in 2. i.e. “The transaction capacity of that blockchain was saturated, so we could not use the smart contract.”

Note 1: “chain” is often used as shorthand for “blockchain”. People refer to data that is stored in a block as “on-chain”, and to code that is executed in blocks that have achieved consensus as being executed “on-chain”. It is correct to modify these usages of blockchain by identifying the specific blockchain you are referring to. When not specifying an network, the most commonly used production network is assumed. “The Ethereum blockchain” would be assumed to refer to the current Ethereum main net, for example.

Note 2: If you are referring to a specific blockchain and you have not introduced that fact, you should introduce that fact. You can either modify the word blockchain with the name of the blockchain to which you are referring: “Ethereum blockchain”, or skip the word blockchain and simply state the name of the blockchain you are refferring to: “Ethereum”.

B) blockchain technology (compound noun.) — Tech that is necessary implement a Blockchain, as defined above. Blockchain Technology normally includes a consensus mechanism (i.e. PoW, PoS), a persistence layer (usually an event stream tied to the consensus mechanism), and a wire protocol. Those are the unique components that make a blockchain what it is.

NOTE on B): This is really a class of compound nouns — a noun decorated by an the adjective blockchain. “blockchain” in this usage decorates “technology”. Some parts-of-a-whole can be described by decorating the noun (part) with the noun category (whole). So you can say, “blockchain data structure” and still make sense.

Caveat: Don’t include underlying tech in this kind of definition — i.e. don’t call a hash function blockchain tech.

C) blockchain-based (a.) — Use this as an adjective to describe something that requires a blockchain to work. Your decentralized application may be blockchain-based. See the note on B, above, for more adjectival uses.

Caveat: Don’t use blockchain-based to decorate nouns that require only the cryptography, networking, or cs tech primitives underlying a blockchain to work; where the underlying tech is not a blockchain, and is not blockchain-based. There are a number of problems in applied math and cs that blockchain-based systems solve, often in new and unique ways. However, the problems that blockchains solve (BFT, for instance) are not “blockchain-based problems”.

Opinion — Don’t use these:

Here are three ambiguous, but common, uses of the word blockchain (labeled D, E, and F below). It is totally understandable to use the word blockchain in these three ways — it’s convenient in the absence of a more established and complete lexicon. However, these uses are vague and engender confusion — they are not a way to achieve clarity in communications.

D) blockchain (n. DO NOT USE) — A philosophy of science of ambiguous nature. Don’t say: “Governments will be changed by blockchain.” Instead, say: “Governments will be changed by blockchain technology.”, or: “Governments will increase the transparency, security, and functionality of voting systems using blockchain technology.”

E) blockchain (n. DO NOT USE) — A specific, but undeclared, blockchain that the author had in mind when he used the term. Don’t say: “Blockchain made it possible to eliminate the central bank of Foo, stabilizing the economy.” Instead say: “Bitcoin made it possible…” or “Ethereum made it possible…”

F) The Blockchain (n. DO NOT USE) — A stand-in — sometimes capitalized — often used as a proper noun — meaning: Any blockchain, all blockchains, or blockchain technology. If you want to be clear, don’t say: “The blockchain is the new database — get ready to rewrite everything.” Instead say: “Blockchains are the new databases…” or “Blockchain tech is the new db tech…”.

Skipping the indefinite article:

Most of the time, people who use an ambiguous definition of the word blockchain will skip the indefinite article required before a clearly defined use of the term. They will say “We use blockchain for that.” instead of “We use a blockchain for that.” Don’t skip the indefinite article!

When you have to use an ambiguous term or new definition:

If you must use D, E, or F, then you should declare your new definition immediately, as in:

“We are paying close attention to distributed ledger technology, or blockchain, recognizing this may represent the most significant development in many years in payments, clearing and settlement,” Ms. Brainard said.

Ms Brianard did a pretty good job, there. Her definition was darn close to academic usage, almost the same as the oxford dictionary, and she defined it right up front. That’s the way to do it. She could also have just said “…attention to blockchain technology, recognizing…”

See also:

Wikipedia. The Bitcoin glossary.

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