In this instance, Layer 2 refers to a separate network that plugs into a cryptocurrency via off-chain channels.1
This often comes up in conjunction with conversations surrounding the Bitcoin block size debate: specifically around (hypothetically) scaling to enable Visa-like transaction throughput vis-a-vis projects like the Thunder and Lightning network proposals which are often characterized as Layer 2 solutions.2
As Wolfgang Pauli might say, this is not even wrong.
Why? For starters, the comparisons are not the same.
Visa is a credit clearing and authentication network, not a settlement network; in contrast no cryptocurrency has credit lines baked-in. In addition – as I penned a year ago – in practice “settlement” is a legal concept and typically requires ties into the existing legal infrastructure such as courts and legally approved custodians. 3
Two simplified examples: (1) If Bob wanted to settle cash electronically and he lived in just about any country on the globe, the only venue that this electronic cash ultimately settles in right now is a central bank usually via its real-time gross settlement (RTGS) network. And (2), if Bob owned the title to a (dematerialized) security and he is trying to transfer ownership of it to someone else, the security ultimately settles in a central securities depository (CSD) such as the DTCC or Euroclear.
What does this have to do with the world of blockchains and DLT?
As of this writing, no central bank-backed digital currency (CBDC) exists.4 As a consequence, there is no real digital cash settlement taking place on any ledger outside of a banks’ own ledger (yet).
One of the key goals for DLT platforms is to eventually get “cash on-ledger” issued by one or more central bank. For instance, at R3 we are currently working on a couple of CBDC-related projects including with the Bank of Canada and Monetary Authority of Singapore. And other organizations are engaged in similar efforts.
In short, one of the potential advantages of using a CBDC issued onto a distributed ledger is the enabling of network participants (such as financial institutions) to settle dematerialized (digitized) asset transfers without relying on outside reconciliation processes. Delivery versus Payment (DvP), the simultaneous exchange of an asset and its payment, could actually take place on-chain.5
However, today if participants on a distributed ledger wanted to settle a trade in cash on a distributed ledger, they could not. They would still need to settle via external processes and mechanisms, which according to an estimate from Autonomous research, collectively costs the industry $54 billion a year. As a result, the industry as a whole is attempting to reduce and – if possible – remove frictions such as these post-trade processes.6
And according to a recent paper from the Bank of England as well as a new paper from the Federal Reserve, CBDCs are one invention that potentially could reduce some of these associated frictions and processes.
How it theoretically works
So how does that tie back in to a hypothetical Layer 2 or 3, 4, 5, connected to a cryptocurrency network?
Assuming one or more of the Lightning implementations is built, deployed, and goes “into production,” the only object that is being tracked and confirmed is a cryptocurrency.7
Cryptocurrencies, as I have written before, are anarchic: purposefully divorced from legal infrastructure and regulatory compliance.
As a result, it cannot be said that “Layer 2” will act as a settlement layer to anything beyond the cryptocurrency itself, especially since the network it attaches to can at most by design only guarantee probabilistic finality.
In fact, the most accurate description of these add-on networks is that each Lightning implementation requires building completely separate networks run and secured by different third parties: pseudonymous node operators acting as payment processors. What are the service-level agreements applied to these operators? What happens if it is no longer profitable or sustainable to operate these nodes? Who are you going to call when something – like routing – doesn’t work as it is supposed to?
And like most cryptocurrencies, Lightning (the generic Lightning) is developed as a public good, which – as a recent paper explored – may have hurdles from a fiduciary, governance, and accountability perspective.
Assuming the dev teams working on the various implementations solve for decentralized routing and other challenges, at most Lightning will be a clearing network for a cryptocurrency, not electronic cash or securities. Therefore proponents of existing Layer 2 network proposals might want to drop the “settlement” marketing language because settlement probably isn’t actually occurring. Trade confirmations are.
But what about colored coins? Can’t central banks just use the Bitcoin network itself and “peg” bitcoins directly to cash or set-up a Bitcoin-like system that is backed by the central bank itself?
These are tangential to “Layer 2” discussion but sure, they could in theory. In fact, the latter is an idea explored by JP Koning in a soon-to-be published paper on “Fedcoin.” In practice this is probably not ideal for a variety of reasons including: privacy, confidentiality, recourse, security, scalability, public goods problems, and the fact that pseudonymous miners operating outside the purview of national regulatory bodies would be in charge of monetary policy (among many other regulatory compliance issues).
Why not just use an existing database to handle these regulated financial instruments then? This is a topic that has and will fill academic journals in the years to come (e.g., RSCoin). But for starters I recommend looking at a previous post from Richard Brown and two newer posts from Antony Lewis.
There are real, non-aesthetic reasons why aviation designers and manufacturers stopped building planes with more than two or three wings, namely aerodynamics. Creative ideas like Lightning may ultimately be built and deployed by cryptocurrency-related companies and organizations, but it is unclear how or why any regulated enterprise would use the existing proposals since these networks are not being architected around requirements surrounding settlement processes.
Perhaps that will change in time, but laws covering custody, settlement, and payment processing will continue to exist and won’t disappear because of anarchic “Layer 2” proposals. Maybe it is possible to borrow and clone some of the concepts, reusing them for alternative environments, just like some of the “blockchain”-inspired platforms have reused some of the ideas underlying cryptocurrencies to design new financial market infrastructure. Either way, both worlds will continue to co-exist and potentially learn from one another.
- From a word choice, it is arguably a misnomer to call Lightning a “layer” at all because relatively little is being built on top of Bitcoin itself. These new networks are not powered by mining validators whereas colored coin schemes are. [↩]
- While he doesn’t delve too much into any of these specific projects, Vitalik Buterin’s new paper on interoperability does briefly mention a couple of them. Also note that the Teechan proposal is different than Lightning in that the former scales via trusted hardware, specifically Intel’s SGX tech, and sidesteps some of the hurdles facing current Lightning proposals. [↩]
- This topic is a ripe area for legal research as words need to be precisely defined and used. For instance, if bitcoins do not currently “settle” (in the sense that miners and users do not tie on-chain identities into court recognized identity, contract, and ledger systems thereby enabling traditional ownership transfer), does this impact government auctions of seized cryptocurrencies? What was the specific settlement process involved in the auction process and are encumbrances also transferred? It appears in practice, that in these auctions bitcoins do transfer in the sense that new entities take control of the private key(s), is this settlement? [↩]
- An argument can be made that there are at least 3 publicly known exceptions to this, though it depends on the definition of an in-production CBDC. This includes vendors working with: Senegal, Tunisia, and Barbados. [↩]
- In blockchain parlance this is called an “atomic transfer.” [↩]
- It is not just reconciliation processes, it is the actual DvP itself (plus the subsequent “did you get it yet” reconciliation processes). [↩]
- As an aside, what are the requirements for “being in production?” In the enterprise world, there is a difference between being in a sandbox and being in production. Which blockchain(s) have been vetted for and secured against real production level situations and fulfilled functional requirements such as scaling and preserving confidentiality? [↩]