The original public blockchain was devoted to cryptocurrency but it has inspired many families of solutions to more complex problems.  As blockchain-based methods evolved, the language of practitioners also changed.  There is much less talk now of “immutability” and “trust”, and more stress on coordination or orchestration, as well as integrity and resilience.

And yet the word “blockchain” has remained. Indeed, it seems to have become normalized despite the diversity of approaches, and that’s a bit of a problem.

For a while, many writers took care to broaden the idea as “blockchain technologies”. And then “Distributed Ledger Technologies” became popular for its generality and as a point of distinction.

Yet the awkward truth is that some of the latest ledger technologies are not terribly distributed or decentralized at all.  IBM’s High Security Blockchain Network for instance can run on a single mainframe.  Thus, the alternative Shared Ledger Technologies has been put forward by payments analyst David Birch, who likes to call out newer algorithms that do not actually involve chains of blocks.

Curiously, most of the leading ledger technology labs have returned to the safety of “blockchain”. Hyperledger, IBM, Microsoft and R3 all call their solutions “blockchain” with little or no qualification. They deny this usage is ambiguous, claiming that the world has come to recognize the term more broadly than the first generation algorithms of Bitcoin and Ethereum.

Of course I acknowledge that the meanings of words change over time.  Some say “cloud” or “Big Data” are comparable terms to “blockchain” insofar as they span ranges of mechanisms and yet each represents a clear technology class.

But I say it’s too early to regard “blockchain” as settled in the same way as cloud or Big Data. Blockchain-based (or inspired) technologies are still emerging rapidly.  There are very few commercially mature implementations, and still no consensus about what these technologies are good for, much less a common appreciation of what they do.

“Blockchain” speaks succinctly of a distinctive architecture and consensus algorithm. A huge body of work continues on the original public blockchains of Bitcoin and Ethereum, each supporting thousands of developers.  These data structures are fundamentally different from the later generation technologies, so generalizing “blockchain” will be misleading to many.

Therefore I would like to find a new word for the whole category of advanced ledger technologies, a label that accurately captures what they are for and what makes them new.

Amidst all the innovation, there is one characteristic which blockchain’s descendants all share: each of them is concerned with orchestrating agreement on some defined state of a data set, across multiple stakeholders, without a leader or central administrator.  

To synchronize consensus is the vitally disruptive aspect of this class of technologies. Synchronization is the one distinctive feature that all blockchains and ledger technologies share, from Bitcoin through Ethereum and Ripple, to Plenum and Hashgraph.

So I’d like to suggest we call all these things Synchronous Ledger Technologies.

Terminology is tricky. I have no illusions about coining a new term, so I merely offer Synchronous Ledger Technology (SLT) for discussion.  It’s a neutral, plain-speaking phrase, and should not disenfranchise anyone’s approach.  

What do you think?