How to bridge cross chain crypto tokens ?

Everything you need to know about bridging cryptocurrency cross-chain by using the RelayChain multi-chain bridge.

What is a native chain “gas” token?

A native chain “gas” token is the token “cryptocurrency” used to pay transactions on that respective block-chain. Every chain has it’s own native “gas” token and the costs per transaction vary per chain.

Always keep a minimal amount of native tokens on that chain so your funds never get stuck. Without the minimal amount you can’t move and sell your tokens “cryptocurrency”.

How to Bridge native USDC stable coins between chains?

Currently we support native USDC stable coin bridging between Ethereum, Polygon, Avalanche and Binance Smart chain.  For more info on the token contracts please check them on the native chain in the right sidebar. 

How does the RelayChain blockchain bridge works?

The RELAY bridge is based on the foundations set by the ChainSafe technology with the principles of lock/mint/burn/release and wrapped tokens mechanisms. Custom code has been added to improve areas like the bridge reliability and stability.

Security and safety are guaranteed by three approaches: Thorough smart contracts/code audits, continuous “white-hat” hacker surveillance, and decentralization of the relayers during a cross chain operation.

Bridging a token back and forth

To accomplish cross-chain transfers, a user wallet sends tokens to the Relay bridge contract and receives them back on the destination chain in the same wallet address

When a token is bridged from the origin chain to the destination chain:

  • Token is locked on the origin chain
  • Token is minted on the destination chain: it becomes a wrapped token (AVAX on Polygon for example). Some tokens are native on multiple chains, like RELAY on all chains supported by the bridge.

When a token is bridged back to its origin chain:

  • Token is burned on the chain where it was minted
  • Token is released on its origin chain

Wrapped tokens vs fungibility.

One drawback of wrapped tokens is the non fungibility issue: Two bridges from two different projects end up with a different (and non compatible) wrapped token of the same token bridged from its native chain. So it means liquidity is fragmented as well on the destination chain, like the need to have 2 liquidity pools for each of the wrapped tokens on the destination chain for the same token transferred from its origin chain.

Some projects have specialized in offering a trade service (1:1 ratio) between two wrapped tokens versions on the destination chain of the same token, but the user is depending on which wrapped tokens are supported by these kinds of projects to (almost) seamlessly use any bridge between the two same chains.

The Relay project is focusing on brokering solid partnerships with well established players in different domains (like DEXs, lending platforms, smart contract platforms) to propagate the wrapped tokens versions by the Relay bridge on the multiple chains supported by the Relay bridge, with enough liquidity everywhere.

The project also seeds initial liquidity with the Relay token and native gas tokens (like ETH, AVAX, MATIC, BNB, etc) on the chains supported by the bridge. This, in addition to other specific project tokens with partners to cross chain and/or set liquidity with Relay (like $QUICK from Quickswap). That way, we can use the Relay bridge to move assets from one chain to another without needing to combine with other bridges to fill in gaps in the cross-chain routes.

Some projects are attempting to solve the fungibility issues, but they have/had been experimental and/or careless with audits, disregarding the security of their users’ funds, and being subjected to major and public known and repeated hacks (like Thorchain, ChainSwap, Poly Network, AnySwap). For the time being, these more exotic cross-chain designs using liquidity bridging, mapping tokens, etc. have proven to be most vulnerable to attack vectors from malicious actors. Users of these bridges have lost funds, sometimes hundreds of millions per incident. For the Relay team, security and safety is paramount. For now, using wrapped tokens has proven to be the most bullet proof method.

The Relay team is exploring new avenues of its own to discover a safe solution to the fungibility problem, but won’t use it until proven safe, scalable and secure.

Solving the conundrum of interoperability in DeFi with seamless, secure and fast executions is one of the biggest challenges today in crypto. The Relay team has amassed a wealth of experience in the bridging space, therefore, they are one of the best positioned to evaluate and execute a way forward without carelessly risking the user funds.

Security with audits.

Security of the smart contracts and bridge code:

  • Chainsafe has been audited by Consensys Diligence
  • Zokyo audited the original smart contracts when the project was formerly known as the Zero Exchange (the initial launch of the bridge, which morphed into Relay)
  • The Relay bridge has been fully audited by Halborn (+ subscribed to their continuous audit monitoring service)

Safety by decentralization — relayers

Another aspect to improve security and safety is decentralization of the relayers: The role of a relayer is to vote (= approve) a cross chain request in order to give the green light to its execution (destination wallet, amount of tokens to lock/mint/burn/release).

There are 5 public relayers, plus one managed by the team, a cast of 4 similar votes is mandatory to approve a cross chain request. To compromise the bridge (like minting more than locked and/or transfer to a different address than the original wallet address, etc), several relayers will need to be hacked at the same time.

The bridge is not fully decentralized in the sense that:

  • The Relay team has delegated the relayers to 5 public and well known entities: Zokyo, Bitcoin Exchange, ChartEx, Avalaunch, Bridge Mutual.
  • Not anyone can decide to be a relayer for the Relay bridge from one day to the other (= like in a full decentralized system). The team appoints them, in order to insure that requirements like the infrastructure is secured, up to scratch to support the bridge volume and not running subpar equipments which would slow down the transactions.
  • There is still the community and a ticketing system where users can register issues and have an interaction with people interfacing with the technical team. In a fully decentralized system, a user could be left on its own, without any idea who to turn to to investigate an issue, nor any assurance how and when it would be resolved.

Ease of integration of new chains — EVM compatibility

When a new chain is EVM compatible, it’s technically easier to add it to the bridge portfolio than one which is not. Although the team’s objective is to also support non EVM compatible chains, like Solana and to consider other similar opportunities.

Gas tokens faucet

When a wallet transfers tokens to a chain for the 1st time, a drip of gas token (like AVAX, HT, BNB, MATIC, MOVR, except ETH) is automatically airdropped on the destination chain to allow for a few trades on the chain. It avoids being stuck with tokens and unable to trade without first going to a CEX for example, buying some gas tokens and send it to the wallet.