A disconcerting actual conversation I had in January:<\/a> a well-meaning non-techie suggested that Uber \u2014 the world-famous “tech unicorn,” that’s a money-haemorrhaging<\/a> minicab firm with a phone app \u2014 was an example of a decentralised system, and a model for how blockchain could succeed.<\/p>\n I think it had never occurred to them before that systems that weren’t utterly centralised in every regard could exist.<\/p>\n “It’s like blockchain, because anyone can sign up to be an Uber driver!” And this was a Londoner, who would have been quite familiar with minicabs and how they work,<\/a> and that the only thing Uber does differently is that you can use an app instead of phoning or going to a minicab office.<\/p>\n But, blockchain!<\/em> Apparently.<\/p>\n <\/p>\n <\/p>\n To be super-brief: A blockchain is a ledger you can only add new entries to \u2014 plus a \u201cconsensus mechanism\u201d to decide who gets to add new entries. More or less.<\/a><\/p>\n I have a non-technical video here,<\/a> and one for techies here,<\/a> with diagrams and answers to the real question \u2014 “yes, but why?”<\/p>\n Blockchains are really simple<\/em>,<\/em> and the usual reaction is: \u201cWhat? That\u2019s not magical at all. How do they get all of this nonsense out of that?\u201d<\/p>\n It gets weird because Bitcoin people started a bit weird.<\/a> But that’s a book in itself.<\/a><\/p>\n What catches the eye of enterprises about “blockchain” seems to be the promises of solving one of these two problems:<\/span><\/p>\n These are genuine needs!<\/p>\n But the first is entirely about the politics of getting organisations working together \u2014 and doing the hard slog of cleaning up your data and formats. (See chapter 11<\/a> of Attack of the 50 Foot Blockchain.<\/a><\/i>)<\/p>\n The second just puts logs in a 1979-style Merkle tree. We did this before “blockchain.”<\/p>\n (This is why Amazon Web Services’ Quantum Ledger Database<\/a> \u2014 which proclaims “owned by a central trusted authority” as a feature<\/em> \u2014 is something that AWS use themselves … and Amazon Managed Blockchain<\/a> isn’t.)<\/p>\n If you have both<\/i> these problems, you have enough of a human\/business mess that applying a blockchain won’t fix either aspect \u2014 though it’ll probably make it all worse.<\/p>\n Occasionally, “blockchain” will be useful as a buzzword to get funding to fix your technical debt.<\/a><\/p>\n Popular “blockchain” advocacy includes a lot of people who have literally never encountered the concept of an even slightly distributed system before \u2014 and then they project at length onto the word “blockchain.”<\/p>\n Bitcoin and blockchain advocates too often seem to think Satoshi invented all the parts of Bitcoin \u2014 that there were no tamper-evident append-only ledgers before Satoshi. Or no distributed systems. Or that there was no open-source software.<\/p>\n Or that there was no cryptography<\/i> before Satoshi. I had a cryptocurrency advocate seriously argue to me<\/a> that we need cryptocurrencies because otherwise, who would work on TLS for secure web browsing?<\/p>\n Lol. Crypto underpins defense, healthcare, finance, infrastructure, and industry. We need people who understand crypto. One lost PKI CA cert jeopardizes HTTPS (SSL\/TLS) “bank level security”. Hopefully, cryptocurrencies result in at least a handful of additional experts qualified to review implementations.<\/p><\/blockquote>\n Back here in reality, cryptography justifies cryptocurrency in the same way that transistors justify crystal healing \u2014 and actual cryptographers get quite reasonably angry at being lumped in with these people.<\/p>\n <\/p>\n \u2513\u250f\u2513\u250f\u2513\u2503 — sarah jeong (@sarahjeong) January 23, 2018<\/a><\/p><\/blockquote>\n
\n“Uh … anyone can sign up to be a minicab driver.”<\/p>\n![\"\"](\"https:\/\/davidgerard.co.uk\/blockchain\/wp-content\/uploads\/2019\/04\/car-on-fire-by-patrick-roper-cc-by-sa-2.0.jpg\")
<\/a><\/p>\nWhat actually is a blockchain, then?<\/h3>\n
What business really wants from “blockchain”<\/h3>\n
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Blockchains didn’t invent distributed systems<\/h3>\n
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\u251b\u2517\u251b\u2517\u251b\u2503\uff3c\u25cb\uff0f
\u2513\u250f\u2513\u250f\u2513\u2503 \/ CRYPTO
\u251b\u2517\u251b\u2517\u251b\u2503\u30ce)
\u2513\u250f\u2513\u250f\u2513\u2503 STANDS
\u251b\u2517\u251b\u2517\u251b\u2503
\u2513\u250f\u2513\u250f\u2513\u2503 FOR
\u251b\u2517\u251b\u2517\u251b\u2503
\u2513\u250f\u2513\u250f\u2513\u2503 CRYPTOGR
\u2503\u2503\u2503\u2503\u2503\u2503 a p h y y y
\u253b\u253b\u253b\u253b\u253b\u253b<\/p>\n