Info Service on UN Sustainable Development (Jun18/13)
20 June 2018
Third World Network
Trust limitations of crypto-currencies & potential ecological
Published in SUNS #8704 dated 20 June 2018
Geneva, 19 Jun (Chakravarthi Raghavan*) - In less than 10 years since
their inception, crypto-currencies have emerged from obscurity to
attract intense interest on the part of businesses and consumers,
as well as central banks and other authorities, but their decentralised
creation have inherent limitations in maintenance of trust in value,
involve vast energy use presaging an environmental disaster and bringing
the internet to a halt.
These are some of the conclusions of the Bank for International Settlements
(BIS) in its in-depth study of crypto-currencies and whether they
could play any role as money. Titled "Cryptocurrencies: looking
beyond the hype", the BIS study, pre-released on 17 June, is
part of its forthcoming annual economic report.
[The study can be accessed at: https://www.bis.org/publ/arpdf/ar2018e5.pdf]
The study notes that the crypto-currencies garner attention because
they promise to replace trust in longstanding institutions, such as
commercial and central banks, with trust in a new, fully decentralised
system founded on the blockchain and related distributed ledger technology
However sophisticated, the BIS study warns that crypto-currencies
are a poor substitute for the solid institutional backing of money,
cannot scale with transaction demand, are prone to congestion, come
with poor efficiency and vast energy use presaging an environmental
disaster and bringing the internet to a halt.
In terms of energy use and ecological disaster, Bitcoin "mining",
one of the early much-hyped crypto-currencies, is estimated in mid-May
by BIS (Graph V.4), to be using as much electricity as a mid-sized
economy such as Switzerland - 60 terawatt-hours per year.
Nevertheless, says BIS, the underlying technology could have promise
in other applications, such as the simplification of administrative
processes in the settlement of financial transactions, though this
still remains to be tested.
BIS notes that many past episodes of monetary instability and failed
currencies illustrate that the institutional arrangements through
which money is supplied matter a great deal. The essence of good money
has always been trust in the stability of its value. And for money
to live up to its property to act as a coordination device facilitating
transactions, it needs to efficiently scale with the economy and be
provided elastically to address fluctuating demand.
These considerations have led to specific institutional arrangements
- the emergence of today's independent and accountable central banks,
after episodes of individual private banks performing this role.
As for cryptocurrencies, they entail economic limitations inherent
in the decentralised creation of trust. For the trust to be maintained,
honest network participants need to control the vast majority of computing
power, and each and every user needs to verify the history of transactions.
And the supply of the cryptocurrency needs to be predetermined by
its protocol. Trust can evaporate at any time because of the fragility
of the decentralised consensus through which transactions are recorded.
Not only does this call into question the finality of individual payments,
but it also means that a cryptocurrency can simply stop functioning,
resulting in a complete loss of value.
Money, BIS notes, plays a crucial role in facilitating economic exchange.
Before its advent millennia ago, goods were primarily exchanged for
the promise to return the favour in the future (traded IOUs). However,
as societies grew larger and economic activity expanded, it became
harder to keep a record of ever more complex IOUs, and default and
settlement risks became concerns. Money and the institutions issuing
it came into existence to address this growing complex ity and the
associated difficulty in maintaining trust.
Money has three fundamental and complementary roles as: (i) a unit
of account; (ii) a medium of exchange; and (iii) a store of value,
enabling users to transfer purchasing power over time. To fulfil these
functions, money needs to have the same value in different places
and to keep a stable value over time. However, maintaining trust in
the institutional arrangements through which money is supplied has
been the biggest challenge.
Around the world, in different settings and at different times, money
started to rely on issuance by centralised authorities. It evolved
from the stamp of a sovereign certifying a coin's value in transactions,
to bills of exchange intermediated by banks developed as a way for
merchants to limit the costs and risks of travelling with large quantities
However, historical experience also made clear an underlying trade-off:
currencies that are supplied flexibly can also be debased easily.
Sustained episodes of stable money are historically much more of an
exception than the norm. "In fact, trust has failed so frequently
that history is a graveyard of currencies."
History proves that money can be fragile, whether supplied through
private means in a competitive manner, or by a sovereign as a monopolist
supplier. Government-backed arrangements have not always worked well
either. Avoiding abuse by the sovereign has thus been a key consideration
in the design of monetary arrangements.
The quest for solid institutional underpinning for trust in money
eventually culminated in the emergence of today's central banks. The
tried, trusted an d resilient way to provide confidence in money in
modern times is the independent central bank, with agreed goals: clear
monetary policy and financial stability objectives; operational, instrument
and administrative independence; and democratic accountability, so
as to ensure broad-based political support and legitimacy.
Independent central banks have largely achieved the goal of safeguarding
society's economic and political interest in a stable currency.
In almost all modern-day economies, money is provided through a joint
public-private venture between the central bank and private banks,
with the central bank at the system's core. Electronic bank deposits
are the main means of payment between ultimate users, while central
bank reserves are the means of payment between banks.
In this two-tiered system, trust is generated through independent
and accountable central banks, which back reserves through their asset
holdings and operational rules. In turn, trust in bank deposits is
generated through a variety of means, including regulation, supervision
and deposit insurance schemes, many ultimately emanating from the
As part of fulfilling their mandate to maintain a stable unit of account
and means of payment, central banks take an active role in supervising,
overseeing and in some cases providing the payments infrastructure
for their currency. The central bank's role includes ensuring that
the payment system operates smoothly and seeing to it that the supply
of reserves responds appropriately to shifting demand, i.e. ensuring
an elastic money supply.
Thanks to the active involvement of central banks, today's diverse
payment systems have achieved safety, cost-effectiveness, scalability
and trust that a payment, once made, is final.
Payment systems are safe and cost-effective, handling high volumes
and accommodating rapid growth with hardly any abuse and at low costs.
In today's sophisticated economies, the volume of payments is huge,
equal to many multiples of GDP.
Despite these large volumes, expanding use of the instrument does
not lead to a proportional increase in costs. This is important, since
an essential feature of any successful money and payment system is
how widely used it is by both buyers and sellers: the more others
connect to a particular payment system, the greater one's own incentive
to use it.
Users not only need to have trust in money itself, they also need
to trust that a payment will take place promptly and smoothly: "finality"
in certainty of payment, and the related ability to contest transactions
that may have been incorrectly executed.
Finality requires that the system be largely free of fraud and operational
risks, at the level of both individual transactions and the system
as a whole. Strong oversight and central bank accountability both
help to support finality and hence trust.
While most modern-day transactions occur through means ultimately
supported by central banks, over time a wide range of public and private
payment means has emerged. Money is typically based on one of two
basic technologies: so called "tokens" or accounts.
Token-based money - banknotes or physical coins - can be exchanged
in peer-to-peer settings, but such exchange relies critically on the
payee's ability to verify the validity of the payment object - with
cash, the worry is counterfeiting. By contrast, systems based on account
money depend fundamentally on the ability to verify the identity of
the account holder.
Cryptocurrencies aspire to be a new form of currency and promise to
maintain trust in the stability of their value through the use of
They consist of three elements. First, a set of rules (the "protocol"),
computer code specifying how participants can transact. Second, a
ledger storing the history of transactions. And third, a decentralised
network of participants that up date, store and read the ledger of
transactions following the rules of the protocol. With these elements,
advocates claim, a cryptocurrency is not subject to the potentially
misguided incentives of banks and sovereigns.
Cryptocurrencies are digital, aspiring to be a convenient means of
payment and relying on cryptography to prevent counterfeiting and
fraudulent transactions. Although created privately, they are no one's
liability, i.e. they cannot be redeemed, and their value derives only
from the expectation that they will continue to be accepted by others.
And, last, they allow for digital peer-to-peer exchange.
Compared with other private digital moneys such as bank deposits,
the distinguishing feature of cryptocurrencies is digital peer-to-peer
exchange. Cryptocurrency transfers can in principle take place
in a decentralised set ting without the need for a central counterparty
to execute the exchange.
The technological challenge in digital peer-to-peer exchange is the
so-called "double-spending problem." Any digital form of
money is easily replicable and can thus be fraudulently spent more
than once. Digital information can be reproduced more easily than
physical banknotes. For digital money, solving the double-spending
problem requires, at a minimum, that someone keep a record of all
Prior to cryptocurrencies, the only solution was to have a centralised
agent do this and verify all transactions. Cryptocurrencies overcome
the double-spending problem via decentralised record-keeping through
what is known as a "distributed ledger". The ledger starts
with an initial distribution of cryptocurrency and records the history
of all subsequent transactions.
An up-to-date copy of the entire ledger is stored by each user, making
it "distributed". With a distributed ledger, peer-to-peer
exchange of digital money is feasible: each user can directly verify
in their copy of the ledger whether a transfer took place and that
there was no attempt to double-spend.
While all cryptocurrencies rely on a distributed ledger, they differ
in terms of how the ledger is updated. One can distinguish two broad
classes, with substantial differences in their operational setup.
One class, based on "permissioned" DLT, are similar to conventional
payment mechanisms. In this class, to prevent abuse, the ledger can
only be updated by trusted participants, or what is known as "trusted
nodes", in the cryptocurrency. These nodes are chosen by, and
subject to oversight by, a central authority of the ledger: e.g. the
firm that developed the cryptocurrency.
Thus, while cryptocurrencies based on permissioned systems differ
from conventional money in terms of how transaction records are stored
(decentralised versus centralised), they share with it the reliance
on specific institutions as the ultimate source of trust.
In a much more radical departure from the prevailing institution-based
setup, a second class of cryptocurrencies promises to generate trust
in a fully decentralised setting using "permissionless"
DLT. The ledger recording transactions can only be changed by a consensus
of the participants in the currency: while anybody can participate,
nobody has a special key to change the ledger.
The concept of permissionless cryptocurrencies, laid out for Bitcoin,
is based on a specific type of distributed ledger, the "blockchain",
updated in groups of transactions called blocks. Blocks are then chained
sequentially via the use of cryptography to form the blockchain. This
concept has been adapted to countless other cryptocurrencies.
Blockchain-based permissionless cryptocurrencies have two groups of
participants: "miners" who act as bookkeepers and "users"
who want to transact in the cryptocurrency. At face value, the idea
underlying these cryptocurrencies is simple: instead of a bank centrally
recording transactions underlying this setup, the key feature of these
cryptocurrencies is the implementation of a set of rules (the protocol)
that aim to align the incentives of all participants so as to create
a reliable payment technology without a central trusted agent.
The protocol determines the supply of the asset in order to counter
debasement - for example, in the case of Bitcoin, it states that no
more than 21 million bitcoins can exist. In addition, the protocol
is designed to ensure that all participants follow the rules out of
self-interest, i.e. that they yield a self-sustaining equilibrium.
The rules entail a cost to updating the ledger, requiring in most
cases a "proof-of-work", mathematical evidence that a certain
amount of computation al work has been done, in turn calling for costly
equipment and electricity use. It is often referred to as "mining".
In return for their efforts, miners receive fees from the users -
and, if specified by the protocol, newly minted cryptocurrency.
Second, all miners and users of a cryptocurrency verify all ledger
updates, which induces miners to include only valid transactions.
If a ledger update includes an invalid transaction, it is rejected
by the network and the miner's rewards are voided. The verification
of all new ledger updates by the network of miners and users is thus
essential to incentivise miners to add only valid transactions.
Third, the protocol specifies rules to achieve a consensus on the
order of updates to the ledger.
With these key ingredients, it is costly - though not impossible -
for any individual to forge a cryptocurrency.
Cryptocurrencies such as Bitcoin promise to deliver not only a convenient
payment means based on digital technology, but also a novel model
of trust. Yet delivering on this promise hinges on a set of assumptions:
that honest miners control the vast majority of computing power, that
users verify the history of all transactions and that the supply of
the currency is predetermined by a
These assumptions give rise to two basic questions regarding the usefulness
of cryptocurrencies. First, does this cumbersome way of trying to
achieve trust come at the expense of efficiency? Second, can trust
truly and always be achieved?
A key potential limitation in terms of efficiency is the enormous
cost of generating decentralised trust. Individual facilities operated
by miners can host computing power equivalent to that of millions
of personal computers.
At the time of writing (25 May), BIS estimates the total electricity
use of Bitcoin mining equalled that of mid-sized economies such as
Switzerland; and other cryptocurrencies also use ample electricity.
Put in the simplest terms, the quest for decentralised trust has quickly
become an environmental disaster.
But the underlying economic problems go well beyond the energy issue,
and r elate to the signature property of money: to promote "network
externalities" among users and thereby serve as a coordination
device for economic activity. The shortcomings of cryptocurrencies
in this respect lie in three areas: scalability, stability of value
and trust in the finality of payments.
First, cryptocurrencies simply do not scale like sovereign moneys.
At the most basic level of decentralised trust, cryptocurrencies require
each and every user to download and verify the history of all transactions
ever made, including amount paid, payer, payee and other details.
With every transaction adding a few hundred bytes, the ledger grows
substantially over time.
For example, (in mid-May), the Bitcoin blockchain was growing at around
50 GB per year and stood at roughly 170 GB. Thus, to keep the ledger
size and the time needed to verify all transactions (which increases
with block size) manageable, cryptocurrencies have hard limits on
the throughput of transactions.
To process the number of digital retail transactions currently handled
by selected national retail payment systems, even under optimistic
assumptions, the size of the ledger would swell well beyond the storage
capacity of a typical smartphone in a matter of days, beyond that
of a typical personal computer in a matter of weeks and beyond that
of servers in a matter of months.
But the issue goes well beyond storage capacity, and extends to processing
capacity: only supercomputers could keep up with verification of the
incoming transactions. The associated communication volumes could
bring the internet to a halt, as millions of users exchanged files
on the order of magnitude of a terabyte.
Another aspect of the scalability issue is that updating the ledger
is subject to congestion. Transactions have at times remained in a
queue for several hours, interrupting the payment process. This limits
cryptocurrencies' usefulness for day-to-day transactions such as paying
for a coffee or a conference fee, not to mention for wholesale payments.
Thus, the more people use a cryptocurrency, the more cumbersome payments
become. This negates an essential property of present-day money: the
more people use it, the stronger the incentive to use it.
The second key issue with cryptocurrencies is their unstable value,
due to the absence of a central issuer with a mandate to guarantee
the currency's stability, a role in which well-run central banks succeed
in stabilising the domestic value of their sovereign currency by adjusting
the supply of the means of payment in line with transaction demand.
This contrasts with a cryptocurrency, where generating some confidence
in its value requires that supply be predetermined by a protocol,
preventing it from being supplied elastically. Therefore, any fluctuation
in demand translates into changes in valuation.
This outcome is not coincidental. Keeping the supply of the means
of payment in line with transaction demand requires a central authority,
typically the central bank, which can expand or contract its balance
sheet. The authority needs to be willing at times to trade against
the market, even if this means taking risk onto its balance sheet
and absorbing a loss.
In a decentralised network of cryptocurrency users, there is no central
agent with the obligation or the incentives to stabilise the value
of the currency: whenever demand for the cryptocurrency decreases,
so does its price.
Further contributing to unstable valuations is the speed at which
new cryptocurrencies - all tending to be very closely substitutable
with one an other - come into existence, with several thousand now
estimated to be in existence. As in past private banking experiences,
the outcome of such liberal issuance of new moneys is rarely stability.
The third issue concerns the fragile foundation of the trust in cryptocurrencies.
This relates to uncertainty about the finality of individual payments,
as well as trust in the value of individual cryptocurrencies.
In mainstream payment systems, once an individual payment makes its
way through the national payment system and ultimately through the
central bank books, it cannot be revoked. In contrast, permissionless
cryptocurrencies cannot guarantee the finality of individual payments.
The lack of payment finality is exacerbated by the fact that cryptocurrencies
can be manipulated by miners controlling substantial computing power,
a real possibility given the concentration of mining for many cryptocurrencies.
Finality will always remain uncertain.
Not only is the trust in individual payments uncertain, but the underpinning
of trust in each cryptocurrency is also fragile. This is due to "forking",
a process whereby a subset of cryptocurrency holders coordinate on
using a new version of the ledger and protocol, while others stick
to the original one. In this way, a cryptocurrency can split into
two subnetworks of users.
An episode on 11 March 2013 is noteworthy because - counter to the
idea of achieving trust by decentralised means - it was undone by
centralised coordination of the miners. On that day, an erroneous
software update led to incompatibilities between one part of the Bitcoin
network mining on the legacy protocol and another part mining using
an updated one.
For several hours, two separate blockchains grew; once news of this
fork spread, the price of bitcoin tumbled by almost a third. The fork
was ultimately rolled back by a coordinated effort whereby miners
temporarily departed from protocol and ignored the longest chain.
But many transactions were voided hours after users had believed them
to be final.
An even more worrying aspect underlying such episodes is that forking
may only be symptomatic of a fundamental shortcoming: the fragility
of the decentralised consensus involved in updating the ledger and,
with it, of the underlying trust in the cryptocurrency.
Overall, decentralised cryptocurrencies suffer from a range of shortcomings.
The main inefficiencies arise from the extreme degree of decentralisation:
creating the required trust in such a setting wastes huge amounts
of computing power, decentralised storage of a transaction ledger
is inefficient and the decentralised consensus is vulnerable.
Some of these issues might be addressed by novel protocols and other
advances. But others seem inherently linked to the fragility and limited
scalability of such decentralised systems. Ultimately, this points
to the lack of an adequate institutional arrangement at the national
level as the fundamental shortcoming.
While cryptocurrencies do not work as money, the underlying technology
may have promise in other fields. A notable example is in low-volume
cross-border payment services. More generally, compared with mainstream
centralised technological solutions, DLT can be efficient in niche
settings where the benefits of decentralised access exceed the higher
operating cost of maintaining multiple copies of the ledger.
Permissioned cryptopayment systems may also have promise with respect
to small-value cross-border transfers, which are important for countries
with a large share of their workforce living abroad. Global remittance
flows total more than $540 billion annually. While cryptopayment systems
are one option to address these needs, other technologies are also
being considered, and it is not clear which will emerge as the most
More important use cases are likely to combine cryptopayments with
sophisticated self-executing codes and data permission systems.
The rise of cryptocurrencies and related technology brings to the
fore a number of policy questions. Authorities are looking for ways
to ensure the integrity of markets and payment systems, to protect
consumers and investors, and to safeguard overall financial stability.
An important challenge is to combat illicit usage of funds. At the
same time, authorities want to preserve long-run incentives for innovation
and, in particular, maintain the principle of "same risk, same
These are largely recurrent objectives, but cryptocurrencies raise
new challenges and potentially call for new tools and approaches.
A related question is whether central banks should issue their own
central bank digital currency (CBDC).
A first key regulatory challenge is anti-money laundering (AML) and
combating the financing of terrorism (CFT). Because cryptocurrencies
are anonymous, it is hard to quantify the extent to which they are
being used to avoid capital controls or taxes, or to engage in illegal
transactions more generally.
A second challenge encompasses securities rules and other regulations
ensuring consumer and investor protection. Fraud issues also plague
initial coin offerings (ICOs). An ICO involves the auctioning of an
initial set of cryptocurrency coins to the public, with the proceeds
sometimes granting participation rights in a startup business venture.
Many of these projects have turned out to be fraudulent Ponzi schemes.
A third, longer-term challenge concerns the stability of the financial
system. It remains to be seen whether widespread use of cryptocurrencies
and related self-executing financial products will give rise to new
financial vulnerabilities and systemic risks.
Close monitoring of developments will be required. And, given their
novel risk profiles, these technologies call for enhanced capabilities
of regulators and supervisory agencies. In some cases, such as the
execution of large-value, high-volume payments, the regulatory perimeter
may need to expand to include entities using new technologies, to
avoid the build-up of systemic risks.
The need for strengthened or new regulations and monitoring of cryptocurrencies
and related crypto-assets is widely recognised among regulators across
the globe. In particular, a recent communique of the G20 Finance Ministers
and Central Bank Governors highlights issues of consumer and investor
protection, market integrity, tax evasion and AML/CFT, and calls for
continuous monitoring by the international standard-setting bodies.
It also calls for the Financial Action Task Force to advance global
implementation of applicable standards.
However, the design and effective implementation of strengthened standards
are challenging. Legal and regulatory definitions do not always align
with the new realities. The technologies are used for multiple economic
activities, which in many cases are regulated by different oversight
Operationally, the main complicating factor is that permissionless
cryptocurrencies do not fit easily into existing frameworks. In particular,
they lack a legal entity or person that can be brought into the regulatory
perimeter. Their legal domicile - to the extent they have one - might
be offshore, or impossible to establish clearly. As a result, they
can be regulated only indirectly.
To implement a regulatory approach, three considerations are relevant.
First, the rise of cryptocurrencies and crypto-assets calls for a
redrawing of regulatory boundaries. Second, the interoperability of
cryptocurrencies with regulated financial entities could be addressed.
Third, regulation can target institutions offering services specific
to cryptocurrencies. To avoid leakages, the regulation would ideally
be broadly similar and consistently implemented across jurisdictions.
SHOULD CENTRAL BANKS ISSUE DIGITAL CURRENCIES?
A related medium-term policy question concerns the issuance of CBDCs,
including who should have access to them. CBDCs would function much
like cash: the central bank would issue a CBDC initially, but once
issued it would circulate between banks, non-financial firms and consumers
without further central bank involvement.
Such a CBDC might be exchanged between private sector participants
bilaterally using distributed ledgers without requiring the central
bank to keep track and adjust balances. It would be based on a permissioned
distributed ledger (Graph V.2), with the central bank determining
who acts as a trusted node.
While the distinction between a general purpose CBDC and existing
digital central bank liabilities - reserve balances of commercial
banks - may appear technical, it is actually fundamental in terms
of its repercussions for the financial system.
A general purpose CBDC - issued to consumers and firms - could profoundly
affect three core central banking areas: payments, financial stability
and monetary policy.
A recent joint report by the Committee on Payments and Market Infrastructures
and the Markets Committee highlights the underlying considerations.
It concludes that the strengths and weaknesses of a general purpose
CDBC would depend on specific design features.
The report further notes that, while no leading contenders have yet
emerged, such an instrument would come with substantial financial
vulnerabilities, while the benefits are less clear. At the moment,
central banks are closely monitoring the technologies while taking
a cautious approach to implementation.
Some are evaluating the pros and cons of issuing narrowly targeted
CBDCs, restricted to wholesale transactions among financial institutions.
These would not challenge the current two-tier system, but would instead
be intended to enhance the operational efficiency of existing arrangements.
So far, however, experiments with such wholesale CBDCs have not produced
a strong case for immediate issuance.
[* Chakravarthi Raghavan is the Editor-Emeritus of the SUNS.]