ioTube cross-chain bridge now supports two-way token swaps between IoTeX and Polygon, Ethereum, BSC → tube.iotex.io.

ioTube v4 is IoTeX’s decentralized cross-chain bridge that enables bi-directional token swaps between IoTeX and Ethereum, Binance Smart Chain, and now Polygon (Matic)! Starting now, Polygon tokens can live on IoTeX and IoTeX tokens can live on Polygon! We are excited to take this major leap in expanding the footprint of IoTeX to Polygon, one of the fastest growing blockchain networks in the world, to broaden the utility of IOTX + XRC20 tokens and bring new liquidity to the IoTeX Network.

Adding Polygon support to our ioTube cross-chain bridge is just the first milestone in our long-term partnership with Polygon. In the future, we will activate more exciting use cases including bringing “Real-World NFTs” and smart device data to the Polygon network — learn more about our partnership with Polygon below:

ioTube v4: Connecting IoTeX & Polygon

With ioTube, IoTeX and Polygon users can enjoy a seamless cross-chain swapping experience with ultra-low fees. Even better, ioTube is fully open-sourced on GitHub and compatible with the ioPay & Metamask wallets for a seamless user experience.

Ready to get started? Just visit tube.iotex.io and check out our step-by-step tutorial on how to convert tokens between IoTeX & Polygon. The first class of Polygon tokens that are now available are: MATIC, wMATIC (wrapped), wETH, wBTC, DAI, USDT, USDC, SUSHI, QUICK, AAVE.

Don’t see your favorite token on this list? No worries! We will be adding many more Polygon tokens in the near future — let us know which ones you want to see next by contacting us on Telegram or Discord.

ioTube v4 — Overview & Architecture

ioTube utilizes multiple smart contracts on both the origin/destination blockchain to enable cross-chain token transfers. It starts when a user deposits assets into a “cashier contract” on Chain A, which is an event that is observed by multiple witness nodes. These witnesses verify this event and send a signature to the relayer network, which aggregates all signatures and instructs a “validator contract” on Chain B to mint the same amount of tokens that were deposited on Chain A.

The ioTube v4 architecture is composed of the following contracts:

• WitnessList : stores the list of active witnesses
• TokenList : stores the list of whitelisted tokens
• TokenSafe : stores the tokens deposited to the token cashier, and these stored tokens are used to transfer to recipients by transfer validator
• MinterPool : holds the minter authorities of all mintable tokens
• TokenCashier : accepts token/coin deposits and emit a receipt for each deposit
• TransferValidator : validates witness signatures and then withdraws tokens from token safe to recipients.

For depositing assets, the TokenCashier contract validates the following:

• Checks if the asset is listed and active
• Checks if the amount is within the maximum limits
• Checks if the asset is a proxy token (e.g., ioETH on IoTeX is a proxy token)
• If proxy, burns it and create a receipt; if not proxy, deposits it into the TokenSafe.

Once a witness detects a deposit, they will sign an attestation and send it to the relayer, which collects attestation from witnesses and submit them to TransferValidator

For minting (i.e., issuing corresponding assets), the TokenValidator contract ensures:

• The asset being converted is whitelisted and active via TokenList
• The transfer has attestations from at least two-thirds of all witnesses
• If so, the contract mints proxy tokens to transfer tokens to the given recipient.

That’s it! After tokens are converted between IoTeX and Polygon, Ethereum, and BSC, they may be traded on respective decentralized exchanges: mimo (IoTeX), Quickswap (Polygon), Uniswap (Ethereum), PancakeSwap (BSC). Stay tuned for even more cross-chain integrations to leading blockchain networks in the future.

Ready to get started with ioTube?

Ready to bring your crypto-assets to the IoTeX Network? It’s easy — just download ioPay for Mobile or Desktop, visit the ioTube website, and follow our step-by-step instructions for Polygon-IoTeX, Ethereum-IoTeX, BSC-IoTeX. For any questions, please reach out to an Admin on Telegram or Discord.

About IoTeX

Founded as an open-source platform in 2017, IoTeX is building the Internet of Trusted Things, an open ecosystem where all “things” — humans, machines, businesses, and DApps — can interact with trust and privacy. Backed by a global team of 30+ top research scientists and engineers, IoTeX combines blockchain, secure hardware, and confidential computing to enable next-gen IoT devices, networks, and economies. IoTeX will empower the future decentralized economy by “connecting the physical world, block by block”.

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