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We provide the Polkadot community with simple usage and high-performance advanced functionalities through Substrate pallets by crypto best practices virtual integration.

Abstract

In this proposal, we implement a crypto-friendly Substrate scaffold and realize privacy and scaling functionalities. Every library is fully compatible with Substrate (no_std and SCALE support) and provided community as open source libraries.

Full compatible libraries can be imported by existing Substrate pallets thus every parachain can use high-performance privacy and scaling functionalities and other crypto projects can implement their functionalities by combining libraries. The same scaffold-based functionalities allow simple usage, high performance, and composable between functionalities.

With our libraries, we can empower existing parachains and accelerate future crypto projects. Full proposal is here.

What’s new?

Zero-knowledge proof Plonk-based construction is new to the Polkadot. Plonk can set up params independent from functionalities thus params can be used for various types of functionalities. Our implementation is the first Polkadot compatible (no_std and SCALE) Plonk as far as we know.

Additionally, we replace the hash function, signing algorithm, and arithmetic domain with an efficient scheme for Plonk. Not only the sidechain but also the mainchain is optimized based on Plonk. This is hard for existing blockchains and a trick of simple usage and high performance.

Why Polkadot

We think that the most significant feature of the Polkadot is the Substrate pallet system because it allows best practices virtual integration.

It’s hard for traditional blockchains to upgrade their infrastructure runtime and storage. When they support new functionalities, they need to extend their blockchain by precompile, off-chain relayer, and so on. This causes complex usage, expensive gas cost, and less development flexibility.

However, the Substrate pallet system allows blockchains to replace blockchain infrastructure runtime and data structure with an efficient and suitable for processing crypto functionalities. This significant feature unlocks blockchain potential and accelerates the next innovation happening in the Polkadot ecosystem.

Additionally, we can share our knowledge with other Polkadot projects, stack the best practice, and improve the Substrate scaffold. This causes synergy between compatible functionalities and enhances Polkadot Network value.

Details

In this project, we implement Substrate crypto-friendly scaffold pallets and realize privacy and scaling functionalities. Deliverables are as follows.

As this was proposed on 4.25.2023, we improved and added some deliverables. We implement every crypto primitive from scratch. Deliverables consist of Substrate crypto-friendly scaffold, ZkRollup, and privacy-preserving transactions. Unique features are as follows.

Substrate crypto-friendly scaffold

1. Full SCALE and no_std Compatible
2. Avoid Code Duplication
3. Replace with new Algorithm Easily

Firstly, the main issue is runtime compatibility. We have been working on crypto projects and when we tried to use crypto functions on Substrate runtime, we needed to make every library dependency compatible with Polkadot or implement host functions and connect each other with conversion interfaces. This accounted for most of the development workload. To avoid this workload and import directly to Substrate runtime, we implement fully compatible libraries.

Secondly, we think how easy it is to apply optimization is important because performance directly affects the user's experience. We separate the interface and algorithm in order to avoid code duplication and replace them with new algorithms easily.

ZkRollups

1. Crypto-Friendly Signing Algorithm
2. Batch Signature Validation
3. Runtime Compatibility

When we worked on the EVM ZkRollups previously, we found that it reduced gas costs and the prover process was not so heavy as it could be done on the GitHub Actions environment.

However, users were necessary to create layer2-specific wallets aside from the main blockchain, and the prover cost was not optimized.

We integrate the wallet between layer 2 and the main blockchain to avoid wallet recreation and, replace the signing algorithm with an efficient hash function and curve, and introduce batch signature validation to reduce the prover workload by native field proving. This ZkRollup works in a WASM environment.

Privacy-Preserving Transactions

1. Account-Based
2. Auditable
3. Plonk

When we worked on the confidential transfers previously, we found that audibility was necessary because of recent regurgitation and UTXO-base was inefficient perspectives from zero-knowledge proof and on-chain memory space.

We implement the first account-based privacy-preserving transactions with Plonk. This privacy-preserving transaction is auditable and saves computation and memory space because of account-based. Account-based is also useful when we extend transaction functionalities and interact with other crypto schemes.

Progress

19 out of 31 milestones were completed.

Polkadot Compatible Crypto Primitive

• Zero Knowledge Proof Standard
• ElGamal Encryption
• Jubjub curve
• Bls12 381
• Polynomial Commitment
• Redjubjub Signature
• ZkSnarks Primitive
• Tate Pairing

Substrate Pallet Functionalities

• RedDSA Wallet CLI Tutorial  
• Encrypted Balance
• Zero Knowledge Friendly Substrate Runtime
• Confidential Transfer
• Plonk on Substrate

Past Activities

Web3 Foundation Grant

• ZkRollups: EVM ZkRollups W3F grant collaboration with Astar Network

https://github.com/w3f/Grants-Program/blob/master/applications/zk-rollups.md https://github.com/AstarNetwork/ZKRollups

• ZkPlonk: Polkadot compatible Plonk W3F grant collaboration with Astar Network

https://github.com/w3f/Grants-Program/blob/master/applications/zk-plonk.md https://github.com/AstarNetwork/plonk

• Privacy Transfer: Account-base privacy transfer transaction

https://github.com/w3f/Grants-Program/blob/master/applications/zero-network.md https://github.com/KogarashiNetwork/Kogarashi/tree/master/pallets/confidential_transfer

Substrate Builder Program

• Deliverly Milestone 1
  https://twitter.com/KogarashiCrypto/status/1684396867944349696

Legal Structure

•  Registered Address

2F・3F Emblem Nishiarai, 3-33-6 Umejima, Adachi City, Tokyo-to 121-0816, Japan

•  Registered Legal Entity

Invers Inc.

About Us

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