Beyond the Trilemma: zk-Rollups and the Future of Scalable Blockchain Networks
Last updated
Last updated
One of the most prominent obstacles in crypto is known as the blockchain trilemma. Coined by Vitalik Buterin, the trilemma refers to the difficulty of achieving three key objectives simultaneously: decentralization, security and scalability.
Decentralization: Ensures that no single entity controls the network, keeping it open and resistant to censorship.
Security: Protects the network and its assets from attacks, ensuring trust and reliability.
Scalability: Focuses on increasing transaction speeds and network capacity, so the system can handle more users and activities as it grows.
While chains like Bitcoin and Ethereum excel in decentralization and security, they have often struggled with scalability.
This tradeoff ended up leading to high fees and slow transaction times, especially during periods of high network activity. which became a bottleneck for DeFi platforms, NFT projects and more.
So, a question was raised: how can blockchains scale without sacrificing the other two pillars of the trilemma?
This is where innovative technologies, such as rollups, come into play. Rollups are Layer 2 scaling solutions designed to reduce the load on the Layer 1 blockchain while retaining its security and decentralization.
By bundling transactions and processing them off-chain, rollups help ease congestion and lower fees, offering a practical solution to Ethereum’s long-standing scalability problem.
As mentioned, rollups are Layer 2 scaling solutions that aim to reduce the burden on the Layer 1 blockchain by processing transactions off-chain. They take multiple transactions, bundle them into batches, and submit those batches to the Layer 1 for final verification.
In essence, instead of each transaction being processed and validated on the main blockchain (which increases costs and slows down performance), rollups do the heavy lifting off-chain and only use L1 for settlement and data availability.
This process improves transaction throughput — the number of transactions that can be processed per second — while reducing gas fees and keeping the blockchain secure.
There are two primary types of rollups that are currently helping to address blockchain scalability challenges: Optimistic Rollups and Zero-Knowledge Rollups (zk-Rollups).
Both types process transactions off-chain and submit data back to the Layer 1 for finality, but they operate under different mechanisms.
Optimistic Rollups assume that all transactions are valid by default. They rely on a “challenge period,” during which anyone can submit fraud proofs to dispute a transaction they believe to be incorrect.
If a transaction is successfully disputed, it is rolled back and the fraud is penalized. This type of rollup is often considered simpler but can have longer settlement times due to the need for the challenge period.
2. Zero-Knowledge Rollups (zk-Rollups), on the other hand, validate transactions using cryptographic proofs, known as Zero-Knowledge Proofs (ZKPs).
ZPKs proofs ensure that every batch of transactions is valid before it is submitted to the L1. There is no need for a challenge period, making zk-Rollups faster and more secure, but the technology is more complex to implement.
While both types of rollups significantly improve scalability, zk-Rollups stand out for their enhanced privacy and security due to ZKPs. We’ll explore zk-Rollups in greater detail next.
Zk-Rollups operate on the principle of proving transactions are valid before they’re finalized on the main blockchain. Using ZKPs, zk-Rollups confirm transaction accuracy without revealing underlying details, ensuring both security and privacy.
So, how does this work in practice?
In zk-Rollups, computationally heavy processes, such as transaction verification, are moved off-chain, which lightens the load on the base L1. However, the transaction data is still stored on the Layer 1 blockchain for added security.
Instead of posting every single transaction, zk-Rollups group multiple transactions into batches and submit these batches to Layer 1, leading to reduced costs and increased efficiency.
Zk-Rollups function by aggregating transactions into bundles and posting them to the Layer 1 in intervals. These bundles are then validated using zero-knowledge proofs.
In this way, zk-Rollups help ease network congestion by reducing the number of individual transactions posted to the main chain. As a result, gas fees are lowered and transaction throughput is increased.
Here’s a closer look at the technical process:
State Verification: Each zk-Rollup has its own state, which is verified using validity proofs. These proofs guarantee that the state changes (i.e., the effects of transactions) are correct before being submitted back to the Layer 1 chain.
Smart Contract on L1: The smart contract deployed on Layer 1 is responsible for ensuring the integrity of the state changes. It verifies the validity of the transaction bundles and updates the state accordingly.
Sequencers and Operators: A sequencer (or operator) handles the execution and bundling of transactions. The sequencer collects transactions off-chain, processes them, and periodically submits them to Layer 1 in batches, ensuring that zk-Rollups benefit from the cryptographic guarantees provided by ZKPs.
By keeping computations off-chain but retaining critical data on-chain, zk-Rollups strike a balance between scalability, privacy and security, positioning zk-Rollups as one of the most advanced and efficient solutions for solving the blockchain trilemma.
To illustrate how zk-Rollups work, let’s delve into an analogy that makes this complex concept a bit more tangible.
Imagine you claim you have a secret power that allows you to open any lock without a key — quite a bold statement. Naturally, your friends are skeptical and want proof.
One of them challenges you to unlock a particular padlock and you accept. But instead of showing them how you did it, you simply perform the feat: the lock opens, just as you claimed it would.
Your friend is left amazed, they’ve seen undeniable evidence that you can indeed open locks without a key. Yet, your method remains a mystery — they don’t know how you did it or what technique you used, meaning they’re confident in your ability, but your “secret method” stays private.
In the same way, zk-Rollups use ZKPs to confirm that a transaction is legitimate without exposing the actual details of the transaction itself. With zk-Rollups, transactions are validated off-chain, and ZKPs provide a cryptographic guarantee that each transaction is correct before it is posted to the blockchain.
At Haust, we are leveraging zk-Rollups to build a scalable, secure and efficient blockchain network. Our architecture is based on the Polygon CDK. The use of zk-rollups provides for us several key benefits:
Low Cost: By utilizing ZK proofs, zkEVM drastically reduces transaction fees, making it accessible to a wider user base.
High Performance: zkEVM ensures fast network finality, meaning transactions are validated quickly and efficiently.
EVM Equivalence: Developers can deploy smart contracts on zkEVM without having to rewrite code, thanks to full compatibility with existing EVM tools and wallets.
Security: zk-Rollups inherit the security of the Ethereum blockchain while adding additional layers of protection through ZK proofs. This ensures that transactions are valid and that user funds are secure.
Traditional solutions often compromise scalability for security and decentralization, but zk-Rollups are reshaping this dynamic. By leveraging Zero-Knowledge Proofs, zk-Rollups enable high transaction throughput and privacy, tackling scalability without undermining the core values of decentralization and security.
Haust is pushing this innovation forward, using zk-Rollups to create a user-centric DeFi ecosystem that balances efficiency with security. We are prepared to support the demands of modern DeFi while remaining accessible to both developers and end users.
Curious to see where zk-Rollups could take DeFi next? Stay connected with Haust and join us on this journey toward a more scalable and decentralized web.