I had the privilege to give a seminar yesterday on bitcoin and the blockchain, to an engaged group of professionals with lively debate and challenging questions. One member of the audience asked a particularly intelligent question: what is the difference between a distributed ledger and a blockchain?
My immediate response was “there isn’t one, not really – it’s mainly semantics”. But I’ve been brooding all morning – is that correct?
Antony Lewis of Bitsonblocks answers the question with clarity and simplicity (hard to come by in this field).
It turns out that all blockchains are distributed ledgers, but not all distributed ledgers are blockchains. Blockchains distribute data to all participants. Distributed ledgers don’t.
He provides a great diagram:
He also offers some advice:
If you want to include all the initiatives going on, use the term “distributed ledgers”.
If you mean blockchains, where unrelated transactions are bundled into blocks, which are chained together using hashes and (in most cases) broadcast to all participating entities for batch processing, use “blockchains”.
If you like acronyms, use “DLT”: Distributed Ledger Technology
So, my new answer to that question is the same, but with a qualification: “you can use the terms interchangeably, but technically, not all distributed ledgers are blockchains”. Sound good?