Safe uses Waku to power decentralised multisig operations with Harbour

The blockchain ecosystem has long struggled with the fundamental problem of safeguarding security, resilience, and decentralisation without sacrificing accessibility and user experience.

Safe, the leading smart contract wallet infrastructure, has taken significant steps towards resolving this challenge with its Harbour infrastructure.

Harbour aims to make multisig transactions decentralised and permissionless by moving the queue process entirely on-chain. Currently, multisig transactions are coordinated and queued off-chain through centralised services, introducing a tradeoff between usability and decentralisation. 

This suspension of permissionless and decentralised design for accessibility is common in the blockchain ecosystem, but Safe now aims to solve this problem by using the Waku tech stack for on-chain multisig operations with Harbour.

As a modular protocol family for scalable and reliable p2p comms, Waku offers the ideal infrastructure for exchanging signatures and coordinating transactions without relying on centralised services, a crucial requirement to realise Harbour’s trustless design philosophy.

Let’s take a look at how Safe uses Waku to power accessible on-chain multisig operations:

Replacing centralised services with decentralised protocols

While Waku can deliver scalable, reliable, and secure decentralised chat, its true potential lies in its design as a general-purpose communications stack for decentralised digital interaction.

By providing scalable, censorship-resistant, and light-node-friendly communication, Waku makes it possible to replace centralised relays, APIs, and databases with a network of peers exchanging information in real time.

Safe’s implementation of Waku in its Harbour project provides a powerful example of how the Waku stack can be plugged in as a p2p alternative to centralised services. 

A multisignature wallet requires a group of participants to coordinate their actions, with each signer submitting and verifying their part of a transaction. 

This coordination has depended on centralised indices or REST APIs, which introduces unnecessary reliance on trusted infrastructure. By integrating Waku, Safe Harbour enables signature exchange to occur directly within a decentralised network, ensuring resilience, privacy, and independence from intermediaries.

In practice, this means that instead of using a direct communication channel or a centralised server, signers and validators communicate over Waku for secure and private p2p transmission. 

Safe chose to implement Waku for the communication between signers and validators for the following reasons:

• Resilience: Waku is a decentralised p2p comms protocol. There is no trusted relay that can be censored or fail.
• Light-node friendly: Waku is designed to run in resource-restricted environments and end-user clients, including Safe’s web interface.
• Easy to integrate: Waku offers a streamlined setup process for both validators and application frontends.

The initial implementation of Waku in Safe Harbour leverages the JS-Waku SDK, a TypeScript implementation of Waku designed to allow developers to integrate Waku functionality into web applications easily. 

Safe notes that this configuration works well for the web interface but places certain limitations on the validator worker. In the future, Safe aims to improve the validator code to use Waku relay nodes to increase reliability.

Harbour and multisig coordination with ERC-4337

Safe’s integration of Waku into Harbour is part of a larger improvement to the project, which is focused on improving accessibility through the implementation of a native ERC-4337 account for Harbour.

This makes it possible for multiple signers to submit signatures to Harbour in parallel, with validated signatures stored on-chain and fee logic delegated to a paymaster contract that manages sponsorship, quotas, and anti-abuse.

Safe explored a number of paymaster models for Harbour but settled on a Harbour Validator Network due to its maximum accessibility to end-users.

In this configuration, validators are professional actors who lock tokens to gain rights to process signature submissions. This structure shifts the burden of economic accountability away from everyday users while maintaining decentralisation. 

To function effectively, validators and signers need a way to exchange data without relying on trusted relays, and that is where Waku is employed to provide permissionless and resilient p2p communication.

Experimental support for Harbour, powered by Waku and ERC-4337, is now live on the Harbour web interface, which runs a Waku edge node to connect to the validator network.

If you’re interested in integrating p2p comms into your project or helping build Waku’s modular tech stack, head over to our developer documentation to get started.

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