SIP-350: Implement SNX Token Bridging via Wormhole

Author	Aakash Thumaty, Evan Gray, Matt
Status	Rejected
Type	Governance
Network	Ethereum, Optimism & Base
Implementor	TBD
Release	TBD

Simple Summary

Utilize Wormhole’s Wrapped Token Transfers contracts to facilitate the movement of SNX tokens across multiple chains.

Abstract

Bridge SNX to Base and future blockchain networks as required in future-proof fashion that does not need additional dev work, contract upgrades, additional technical debt. This method additionally ensures that users can withdraw their SNX without facing a mandatory lock-in period of 7 days, or seamlessly bridge to other supported chains.

Motivation

Wormhole’s Wrapped Token Transfer (WTT) has been in active operation for close to three years, during which it has facilitated the transfer of over $36 billion in value and processed more than 750 million messages. This change aligns with Synthetix’s expansion goals and adheres to the security protocols outlined in SIP-345. Utilizing the Base bridge as proposed in SIP-338 has the limitations of 1) users being required to wait 7 days to withdraw from Base 2) creating many versions of SNX token that are not compatible with each other (ie ETH-SNX, OP-bridged-SNX, Base-bridged-SNX, X1-bridged-SNX etc will not be fungible) and thus creating an inferior user experience.

Specification

Overview

SNX Bridging: Utilize WTT Contracts for bridging SNX across multiple chains. Simply endorse the token that is bridged using WTT

Key Benefits for SNX Users:

Immediate token bridging without a 7-day waiting period. Using other bridging mechanisms, including but not limited to native bridges like the OP bridge, users have to wait for OP Stacks’ 7 days withdrawal period to pull their SNX from Base to Ethereum or Optimism.
Avoid double-wrapped tokens. Tokens moving between networks will remain fungible regardless of source or destination network.
No modifications to the V2X codebase. The Wrapped Token Transfer contracts work with any existing ERC20s, the ERC20s themselves do not need to be modified in order to be supported. This is the proposed route given Synthetix priorities surrounding not touching the V2X codebase. The WTT contracts lock the V2X ERC 20s as they exist and subsequently mint on the bridged chains.
Capability of SNX in LPing, rewards, and collateralization on multiple chains

Synthetix Protocol Benefits:

Ability to buy and burn SNX tokens for rewards, distributions, or any other ERC 20 use case.
Expansion to future chains without creating technical debt that scales to the number of chains Synthetix deploys to. Wormhole’s WTT continues to expand to new supported chains. Once a token launches as a WTT, there is a minor fixed cost to expand to all of the WTT supported chains.
Unlike other solutions, Wormhole’s Wrapped Token Transfers (WTT) allows for SNX to expand to desired chains on-demand without the need for a contract upgrade and to leverage battle-tested infrastructure. The contracts used to take SNX cross chain exist independent of the token contracts themselves.

Approach

Primary Bridging Method for SNX: Adopt Wormhole’s Wrapped Token Transfer (WTT) Bridge Contracts as the bridging standard for all chains where there is no native SNX token.
Distribution Techniques

Incorporate Connect (https://wormhole.com/connect/) within the Synthetix app (https://staking.synthetix.io/bridge) for direct SNX transfers. This involves using either the direct drop in widget with or without the customization options or directly using the SDK for a more custom UI.
Additionally, SNX transfers will be enabled in Portal (https://www.portalbridge.com/), a well known retail bridge, for redundancy. Portal offers immediate and native gas-efficient SNX token transfers with gasless redeems and optional gas drop with minimal service fees to users.

Security

Wormhole is a fully open-sourced protocol and built in the open. All security controls are fully transparent to developers and end users. The protocol relies on a network of 19 validators (Guardians) to come to supermajority consensus for message validation and governance. Each Guardian is a known, independent, and professional validation company that are widely dispersed geographically across the globe - see their status at any time here.

About Wormhole’s Security Program -

Wormhole has a $2.5 million dollar bug bounty program on Immunefi - https://immunefi.com/bounty/wormhole/.
Has been audited 24 times from top auditing firms like Trail of Bits, Ottersec, Halbourn, and Zellic.
More details about Wormhole’s security (including full audits) here.
Developed and implemented an industry leading security program - see the year-end report here.
Launched the Governor - safety feature that reduces the cross-chain impact of certain exploits by giving Guardians the option to rate limit Wormhole token transfers based on daily and per-transaction thresholds.
Launched the Global Accountant - safety feature which independently verifies token balances on each side of a transfer before a transfer is approved.
Implemented additional defense-in-depth practices like an incident response protocol with Chainalysis and a social media monitoring program.

Independent industry assessment of Wormhole

Uniswap conducted the industry’s first assessment of bridges that examined Wormhole’s trust, decentralization, and security against major bridge competitors. Wormhole was determined to be the most secure option evaluated, and the only bridge approved for deployment without any preconditions. See the specific Wormhole Report and the Uniswap Bridge Assessment

Rationale

The adoption of WTT for SNX bridging offers significant improvements in usability, security, and technical efficiency, supporting Synthetix’s broader strategic goals.

WTT is well adopted by protocols and Layer 1s. To date, WTT

Secures $600 million in value and has helped facilitate north of $36 billion in transfer volume to date.
Is the most trusted provider of wETH and USDC on Solana, Moonbeam, Celo, Sui, and more chains.
Is trusted by projects such as:
Render Network for their Native token migration to Solana
Threshold Network’s tBTC expansion from Ethereum to a series of L2s and Solana and large consumer projects with their roots in Web2 like Sweatcoin’s SWEAT token.
Is being evaluated by the Lido DAO for the canonical wstETH representation on certain chains.