Scalability — it’s ability to increasing the scale of operation of the system or project. In crypto space we usually mean it’s ability to perform more transactions per specified time frame. It’s not easy to extend scalability because of “Blockchain Trilemma” — improvement of scalability might affect security and decentralization. There is multiple approaches of improvement scalability of blockchains:

1. Modification of blockchain’s core with for example extending block space or better compression of transaction data

2. Building structures which are called subsequent layers or sidechains of the main blockchain.

The approach number 2 is found as a crucial but it does not exclude approach number 1 at the same time. Both types of activities can be carried out simultaneously.

Let’s go deeper into 2nd approach. Below listed most popular types of structures that might be built “around” the main blockchain (and examples of existing structures in brackets).

• Sidechains (Polygon, xDai)

• State Channels (Lightning Network)

• Optimistic Rollups (Optimism, Arbitrum)

• Zero-Knowledge Rollups (StarkNet, ZkSync)

Let’s discuss it using the example of Ethereum. All of these structures provide better scalability but there’s the question — which one provide good enough security and decentralization in the meanwhile? Rollups seem to be the “Holy Grail” of blockchain. There are 2 types of rollups — Optimistic and Zero-Knowledge. They inherit the security from the Ethereum blockchain. There are some differences between them so let’s provide the most important advendatages and disadventages of both of them below.

Optimistic:

• EVM compatible (existing Ethereum’s dapps and smart contracts can be executed there)

• Security based on fraud proof

Zero-Knowledge

• Security based on cryptography (validity proofs called SNARKs/STARKs)

• EVM noncomaptible (it requires creating dApps and smart contracts anew but it might change in the future)

In my opinion Zero-Knowledge Rollups are the solution for scalability problem of blockchains.

Scalability — it’s ability to increasing the scale of operation of the system or project. In crypto space we usually mean it’s ability to perform more transactions per specified time frame. It’s not easy to extend scalability because of “Blockchain Trilemma” — improvement of scalability might affect security and decentralization. There is multiple approaches of improvement scalability of blockchains:

1. Modification of blockchain’s core with for example extending block space or better compression of transaction data

2. Building structures which are called subsequent layers or sidechains of the main blockchain.

The approach number 2 is found as a crucial but it does not exclude approach number 1 at the same time. Both types of activities can be carried out simultaneously.

Let’s go deeper into 2nd approach. Below listed most popular types of structures that might be built “around” the main blockchain (and examples of existing structures in brackets).

• Sidechains (Polygon, xDai)

• State Channels (Lightning Network)

• Optimistic Rollups (Optimism, Arbitrum)

• Zero-Knowledge Rollups (StarkNet, ZkSync)

Let’s discuss it using the example of Ethereum. All of these structures provide better scalability but there’s the question — which one provide good enough security and decentralization in the meanwhile? Rollups seem to be the “Holy Grail” of blockchain. There are 2 types of rollups — Optimistic and Zero-Knowledge. They inherit the security from the Ethereum blockchain. There are some differences between them so let’s provide the most important advendatages and disadventages of both of them below.

Optimistic:

• EVM compatible (existing Ethereum’s dapps and smart contracts can be executed there)

• Security based on fraud proof

Zero-Knowledge

• Security based on cryptography (validity proofs called SNARKs/STARKs)

• EVM noncomaptible (it requires creating dApps and smart contracts anew but it might change in the future)

In my opinion Zero-Knowledge Rollups are the solution for scalability problem of blockchains.