What is the blockchain trilemma?
Since its beginning, the
internet was in dire need of digital cash, money that would execute payments
fast and find a use case in the commerce opportunities the digital realm
presents.
Visionaries like the
cypherpunks were in a race to figure it out until eventually…
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What
is blockchain trilemma?
According to Vitalik Buterin, reconciling
scalability, decentralization, and security is the biggest challenge for
blockchain networks. It is a widely held belief that they can support two of
three benefits, and sacrifices are unavoidable. The very concept of Ethereum
2.0 was born out of this trilemma. Why does it matter for crypto investors, and
what are the solutions?
Untangling the trilemma for
decentralized networks
The term blockchain trilemma refers
to the difficulty of putting theory into practice. The technology behind
decentralized finance is way ahead of our times. Although developers know how
it is supposed to function, they struggle to retain all three of the
fundamental features.
In a perfect world, scalability,
decentralization, and security would go hand in hand. Unfortunately, humanity
is yet to develop concepts that can allow their seamless integration. Despite
the dominance of Bitcoin and Ethereum, the mass adoption of public blockchain
networks is hampered by their rigidity. This creates the blockchain trilemma,
as described in the diagram below.
Without solving this puzzle, developers
cannot build a viable replacement for centralized finance. The brightest minds
are hard at work, but Ethereum killers like Polkadot, Cosmos,
and Solana have their flaws. In 2021, Algorand proudly announced that it had
cracked the infamous trilemma. Here are the key things to know about the
problem and its solutions in 2022.
Three pillars of blockchain
technology
Rarely is a perfect balance possible.
Blockchain creators typically make concessions, sacrificing one of the
characteristics. Mastering the trilemma is a task for ambitious developers.
Here is what each of its elements includes:
·
Decentralization. This concept is central to any blockchain, as it underlies
immutability — no single entity has the power to manipulate transactions. As
control over the transferred data is distributed across the network, all of its
participants are equals.
·
Security. To
prevent interference, blockchain networks must be equipped with ironclad
defenses. Otherwise, transaction blocks may vanish, causing payments to
disappear.
·
Scalability. The number of users and transactions is constantly growing. A
blockchain’s ability (or inability) to support this rising demand can seal its
fate. A lack of scalability results in delays and ramped-up fees.
So, why do developers encounter problems
when they try to combine these aspects? Let’s take a deep dive into the
blockchain trilemma.
Blockchain scalability
This challenge impedes the adoption of
Bitcoin and decentralized networks on the whole. Some projects claim to be extremely
scalable — for instance, Solana can support over 7,000 times more transactions per second
(TPS) than Bitcoin. However, most blockchains fail to support a massive user
base seamlessly.
To be fair, nobody knows for sure how many
transactions will make crypto use truly global. Scalability efforts do not
target X users or Y TPS. Instead, it is a degree of efficiency to maintain
24/7.
We can make an educated guess about the
scope by looking at social media. In the first quarter of 2022, Facebook had
roughly 3 billion monthly active users, while Twitter
had around 396.5 million users globally.
Meanwhile, Bitcoin has only around 80
million wallet holders. Its original speed ( up to 7 TPS) is meager compared to global payment
processors like VISA and PayPal. Even Ethereum is more efficient. Given the
transaction fees, which peaked at $62.788 in April 2021, the Bitcoin network may
be reaching its limit.
Scaling Ethereum from its average (15 TPS)
to 6,000 TPS seems to be a giant leap forward. However, this would only suffice
for roughly 50,000 active users whose transactions would be confirmed by
several hundred nodes.
Pros and cons of
scalability
A scalable network supports a growing
workload without detriment to performance or costs. This agility is vital for
protocols in social media, gaming, messaging, and video streaming, as they
require more and more transactions by default.
One of the ways to scale the networks is by
lowering their defenses. Enterprise blockchains adopt permissioned models to
balance decentralization and an extreme throughput. Hyperledger Fabric, for
example, allows only specific users to access and participate in its ecosystem.
Another way to improve scalability is by
switching to another consensus mechanism — in particular, from Proof-of-Work to
Proof-of-Stake. The latter is more sustainable as it replaces miners with
stakers. However, it has its own imperfections, so the blockchain trilemma
remains unsolved.
Blockchain decentralization
The blockchain philosophy is based on a
simple premise: no central entity should be able to manage the transactions.
Decentralized networks are called permissionless to reflect the parity of
participation. Here is how this principle works for Bitcoin and Ethereum, which
both use PoW.
Control is distributed across the network
equally. All transactions are confirmed by miners — individual nodes with the
same powers and privileges. A share of fees paid by users is turned into mining
rewards.
No one party can change the network’s
direction without approval from the nodes. This blockchain technology bestows more
freedom on its participants compared to banking. It is particularly salient
today when corporations and institutions are demonized for freezing accounts
unfairly. As the political tensions deepen, who can guarantee that bankers will
protect dissidents’ assets?
Such fears are pushing blockchains to the
forefront of technological advancement. When perfected, they might ensure
financial freedom for all — at least in the digital space. Yet due to the
blockchain trilemma, decentralization often overshadows scalability.
Pros and cons of
decentralization
Decentralization boosts security. All nodes
in a decentralized network have equal status and influence. Governance-related
issues are discussed through cooperation and proposals for protocol changes.
The more nodes are involved, the harder it is to perform a 51% attack, which gives malevolent users control over
the overall mining power.
If one node gets one vote, the model seems
perfectly democratic, but this does not mean the community is infallible. It
could make flawed proposals due to a lack of moderation. Controversial features
could be brought forward and implemented.
What’s more, the veteran PoW blockchains are
notoriously cumbersome and unsustainable. They require a large amount of mining
power, while the speed is meager, and scalability is beyond reach.
Blockchain security
Without security, blockchain technology
would be worthless. The distribution of control is supposed to make ledgers
immune to tampering. However, quite a few blockchains are susceptible to 51%
attacks. The reason is simple — decentralized technology is open-source. As the
code is publicly available, any cybercriminal can read it and figure out ways
to exploit it.
That said, Bitcoin hacks rarely succeed, but
the use of smart contracts makes its competitors more vulnerable. In 2021, the
simplest way to undermine a project was by exploiting flash loans, a common
DeFi feature.
In a sense, security and scalability are
means of achieving conflicting goals. The former aims to maintain stability and
functionality; the latter allows blockchain networks to expand. In recent
years, developers have become more prone to sacrifice some of the security in
pursuit of scalability and decentralization.
Pros and cons of security
This is the bedrock of any blockchain
network, a feature mandatory for its existence. The most fundamental task of
any blockchain is to create the next block in the chain safely, reliably, and
fast. This is what consensus mechanisms are all about. They must prevent
interference and disruptions. Malicious actors have to take over most nodes to
manipulate the ledger data.
The downside of security is the sheer amount
of resources required for reliable blockchain platforms. PoW-based blockchains
cannot maintain their overall security without a large army of miners. The
trade-off here is scalability and TPS: the more miners participate, the more
difficult it is to support high throughput.
PoW requires substantial computing power and
causes high transaction fees at times of congestion. PoS is lighter but less
secure. Individuals with malicious intent may take control by acquiring a large
number of stake tokens.
Ethereum 2.0 as scalable
and secure decentralized network
The Ethereum roadmap shows a possible
solution to the trilemma. Its dual PoS model includes an execution layer for
smart contracts and a consensus layer for transactions.
When the ecosystem transitions to PoS with
sharding and side chains, it will become more sustainable, agile, and
efficient, with TPS rising to . The transaction fees will also shrink. This
vision incorporates decentralization, security, and scalability.
In March 2022, the team launched the Kiln
testnet, the last “test” blockchain before the Merge — the final transaction to
PoS with stakers instead of miners. The upgrade is expected to reduce energy
consumption by over 99.9%.
Lightning network —
Bitcoin’s response to blockchain trilemma
Bitcoin’s solution to the trilemma is its
second layer for off-chain transactions. It is made up of multiple payment
channels. Managing transactions beyond the mainnet (that is, without block
confirmations) adds scalability to the original security paradigm. In June 2022, the Lightning Network hit the 4,000
Bitcoin public capacity milestone, doubling its results since July 2021.
According to some experts, Bitcoin’s
Lightning protocol will usher in the next generation of decentralized finance.
Each channel can process up to over 250 TPS, while the number of these channels
is unlimited.
How Algorand solved the
blockchain trilemma
Algorand is a programmable blockchain
supporting smart contracts. Validation happens via a proprietary system called
Pure Proof-of-Stake (PPoS). It is the only model to have officially solved the
trilemma.
Users that propose blocks and vote on
proposals are chosen in a random and secret fashion. The system establishes a
new set of committees every time a new block is written. Each node has an
influence proportional to its stake. While other PoS variations connect overall
security to a limited subset of users, PPoS links it to the honesty of the
majority.
This consensus mechanism is based on VRF
(verifiable random function) invented by Algorand’s founder Silvio Micali. The
network is about to achieve 3,000 TPS and could scale to 45,000 TPS in a few
years. Its protocol is currently used by 384 companies.
Blockchain trilemma and
global adoption of blockchain networks
Any decentralized ecosystem must balance
security and scalability. Speedy and affordable transactions are only part of
the equation — a public blockchain must also prevent malicious entities from
tampering with its ledger. In 2022, the blockchain trilemma remains relevant,
and the drive for solving it fuels the ongoing innovation.
While Ethereum is yet to make its scalable
future a reality, Algorand has already offered a solution. Its viability shows
that blockchain developers are on the right track, and widespread adoption is
realistic.
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