Introduction

Starknet is a decentralized layer-2 network that helps Ethereum to scale securely. It uses a cryptographic technique called Zero-Knowledge proofs (ZKPs) to bundle and verify transactions off-chain, before submitting them to Ethereum as a single transaction. This allows Starknet to process thousands of transactions per second with low fees, while still maintaining the security of the Ethereum blockchain.

What are ZKPs?

ZKPs, also known as Zero-knowledge proofs are a cryptographic technique that allows one party (the prover) to prove to another party (the verifier) that they know a piece of information without revealing that information.

💡Here is a simple analogy of how ZKPs work:
Let’s say a prover wants to prove to the verifier that they know the password to a door. The prover and verifier agree on a challenge-response protocol.

For example: the verifier might tell the prover to open the door, then the prover opens the door.

The verifier can now verify that the prover knows the password without ever learning the password itself.

ZKPs can be used to prove much more complex statements than just knowing a password.

Types of ZKPs

Talking about the types of Zero Knowledge proofs. There are two main types of ZKPs namely:

Interactive and Non-interactive

• Interactive ZKPs require the prover and verifier to engage in a back-and-forth conversation. The prover provides responses to the verifier's queries, and the verifier decides whether or not to accept the proof.

• Non-interactive ZKPs do not require any interaction between the prover and verifier. Instead, the prover creates a single, self-contained proof that the verifier can independently verify without further communication.

In addition to these two main types, there are also a number of different subcategories of ZKPs. Some of the most notable subcategories include:

• ZK-SNARKs (Zero-Knowledge Succinct Non-Interactive Arguments of Knowledge): ZK-SNARKs are a type of non-interactive ZKP that is particularly efficient and compact. They are often used in applications where privacy is important, such as blockchain transactions and secure voting systems.

• ZK-STARKs (Zero-Knowledge Scalable Transparent Arguments of Knowledge): ZK-STARKs are another type of non-interactive ZKP that is efficient and compact. They are also transparent, meaning that the verifier can verify the proof without trusting the prover's setup.

• ZK-ORAMs (Zero-Knowledge Oblivious RAMs): ZK-ORAMs are a type of ZKP that can be used to protect the privacy of data that is stored on a server. They allow the client to access the data without revealing to the server which data they are accessing.

Starknet uses ZK-STARKs to bundle and verify transactions off-chain before submitting them to Ethereum. In other words, ZK-STARKs are the cryptographic foundation upon which Starknet is built. Starknet uses ZK-STARKs to prove that transactions are valid without revealing any information about the transactions themselves. This allows Starknet to scale Ethereum without sacrificing security or privacy.

💡Here is a simple example of how ZK-STARKs are used in Starknet:

Suppose a user wants to send a payment to another user on Starknet. The user can create a transaction and submits it to Starknet.

Starknet will then use ZK-STARKs to prove that the transaction is valid without revealing any information about the transaction itself. Starknet bundles the transaction with other transactions into a batch and submits the batch to Ethereum.

Ethereum verifies the batch using the ZK-STARK proofs and updates its state accordingly.

This process allows Starknet to process thousands of transactions per second with low fees.

Overall, ZK-STARKs are a powerful cryptographic powerful tool that makes Starknet a very promising scaling solution for Ethereum, By allowing for the efficient and secure verification of transactions off-chain, ZK-STARKs can help Ethereum to scale and become more accessible to a wider range of users.

Features of Starknet

Starknet offers several features that make it a promising scaling solution for Ethereum, including:

Scalability

Starknet can process thousands of transactions per second, with very low fees. This is a significant improvement over Ethereum's current throughput of around 15 transactions per second.

Security

Starknet uses ZKPs to verify transactions off-chain, before submitting them to Ethereum as a single transaction. This ensures that all transactions on Starknet are valid and secure, even if they are executed off-chain.

Composability

Starknet is fully composable with Ethereum, meaning that developers can build applications on Starknet that can interact with other Ethereum-based applications. This is important for maintaining the interoperability of the Ethereum ecosystem.

Starknet Architecture

Starknet's architecture is composed of several components that work together to enable its highly scalable and secure transaction processing capabilities. These components include:

User Accounts (Wallets)

Starknet user accounts, unlike Ethereum's externally owned accounts (EOAs), are implemented as smart contracts. This flexibility allows for more sophisticated wallet recovery mechanisms and the creation of custom account types.

Full Nodes

Full nodes maintain a complete copy of the Starknet state and validate transactions. They play a crucial role in ensuring the security and decentralization of the network.

Sequencer

The sequencer is a centralized entity that packages transactions into batches and broadcasts them to the network. It plays a vital role in optimizing transaction throughput and reducing latency.

Prover

The prover is a specialized off-chain server that generates ZK-STARK proofs for transaction batches. These proofs demonstrate the validity of transactions without revealing their details, ensuring privacy and scalability.

Verifier

The verifier is a smart contract deployed on the Ethereum blockchain that verifies the ZK-STARK proofs submitted by the prover. This ensures that only valid transactions are finalized and recorded on the Ethereum ledger.

Core Smart Contract

The core smart contract is a central component that manages the overall operation of Starknet. It handles account creation, transaction processing, and interaction with the Ethereum blockchain.

Off-chain Data Availability

To ensure that full nodes can reconstruct the transaction history and verify proofs, off-chain data availability mechanisms are employed. These mechanisms store transaction data in a distributed manner, making it accessible to full nodes without compromising privacy.

Cross-chain Communication

Starknet integrates with the Ethereum blockchain through a bridge mechanism, allowing assets and data to be transferred between the two chains. This enables interoperability between applications deployed on Starknet and Ethereum.

Account Abstraction

Starknet's account abstraction feature allows developers to create custom account types with specific functionalities. This enhances the versatility and flexibility of the platform.

Cairo Programming Language

Starknet contracts and the Starknet OS are written in Cairo, a custom-designed programming language optimized for ZK-STARK proofs and efficient execution.

Starknet's architecture is designed to provide a balance between scalability, security, and decentralization. By utilizing ZK-STARK proofs and off-chain processing, Starknet achieves high transaction throughput while maintaining the security and decentralization of the Ethereum blockchain. The combination of these components makes Starknet a promising solution for scaling Ethereum and enabling a new era of decentralized applications.

Starknet’s Use Cases

Starknet can be used to scale a wide range of Ethereum-based applications, including:

Decentralized exchanges (DEXs): Starknet can be used to build DEXs that can offer fast and low-cost trading.

Non-fungible token (NFT) marketplaces: Starknet can be used to build NFT marketplaces that can handle a large number of transactions per second.

Gaming platforms: Starknet can be used to build gaming platforms that can offer fast and fair gameplay.

Social media platforms: Starknet can be used to build social media platforms that can support a large number of users and transactions.

Ecosystem

The Starknet ecosystem is still under development, but it is growing rapidly. There are a number of projects already building on Starknet, including:

LayerSwap: A DEX that aggregates liquidity from multiple DEXs and offers fast and low-cost trading.

Immutable X: An NFT marketplace that offers fast and low-cost transactions for NFTs.

StarkGate: A bridge that allows users to transfer assets between Ethereum and Starknet.

StarkPay: A payment gateway that allows users to make payments with low fees using Starknet.

Conclusion

Blockchain is the underlying technology that powers Ethereum and Starknet.

Ethereum is a blockchain platform that allows developers to build DAPPS.

Starknet is a promising layer-2 scaling solution for Ethereum that offers several advantages, including scalability, security, and composability. The Starknet ecosystem is still under development, but it is growing rapidly and there are several projects already building on Starknet.