Symbiosis: To/From BTC
The Symbiosis protocol: the implementation of the cross-chain BTC exchange process using the Symbiosis BTC bridge
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The Symbiosis protocol: the implementation of the cross-chain BTC exchange process using the Symbiosis BTC bridge
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This document describes the implementation of the cross-chain BTC exchange process within the Symbiosis protocol using the Symbiosis BTC bridge. It highlights the solutions and approaches used to facilitate cross-chain operations involving BTC. Understanding these mechanisms is important for developers and stakeholders engaged in the deployment and operation of cross-chain exchanges.
Implemented cases:
Bridging BTC two ways:
Wrapping BTC from the Bitcoin network to BNB Chain
Unwrapping BTC from BNB Chain to the Bitcoin network
Exchanging BTC two ways:
Exchanging BTC for another token within a single cross-chain operation across certain supported blockchain networks.
Exchanging a token for BTC within a single cross-chain operation across certain supported blockchain networks.
The implementation of the cross-chain BTC exchange process for a token to BTC within the Symbiosis protocol using the ThorChain BTC bridge is described here:
Forwarder: This component handles user requests to exchange BTC from the Bitcoin network for tokens across other blockchain networks. It generates a unique BTC address for each request, stores the payload for the request, and forwards the received BTC to the intended destination (hence the name “forwarder”). The forwarder implements functionality that isn't available in Bitcoin network smart contracts. The forwarder acts as a custodial wallet; it can be operated by anyone willing to cover the fees for forwarding transactions on the Bitcoin network. Important: the forwarder must be fully trusted. Each integrator can deploy their own forwarder and trust it to process transactions initiated through their integration. Symbiosis, for example, trusts its own forwarder for transactions handled through its WebApp. The forwarder provides compatibility with regular and legacy Bitcoin wallets.
BTC portal: This is a smart contract located on the Bitcoin blockchain, playing a role similar to Portal smart contracts of the Symbiosis protocol on other supported blockchains. Unlike Ethereum Virtual Machine (EVM) smart contracts, its state is validated only by the relayers MPC group. The Bitcoin consensus layer only validates funds moving to or from its address.
Web/mobile apps powered by the Symbiosis web SDK: A UI provided by Symbiosis or an integrator that enables users to access the functionality of the Symbiosis protocol. It uses the Symbiosis SDK/API to compose call data for cross-chain operations and retrieve states stored on Symbiosis smart contracts. This documentation explains how users interact with the protocol using the Symbiosis WebApp. However, any integrator using the Symbiosis API/SDK can provide similar UI and functionality to interact with the Symbiosis protocol.
Relayers network: A blockchain-agnostic, P2P network consisting of registered relayer nodes securitised by the MPC/HTSS scheme. It facilitates the secure and efficient transmission of data between supported blockchain networks, ensuring data integrity and resilience against potential attacks through various technical approaches and crypto-economic incentive mechanisms. For more information about the relayers network, please refer to Relayers network.
Сore smart contracts implement the on-chain logic of cross-chain operations (cross-chain swaps, cross-chain zaps, interchain communication, bridging). The smart contracts are deployed and tuned by Symbiosis administrators while adding a blockchain to the Symbiosis protocol. For more information about the Symbiosis smart contracts, please refer to Symbiosis Routing Contracts.
Wrapping BTC: BTC → syBTC
Symbiosis bridges BTC from the Bitcoin network to BNB Chain by wrapping it into syBTC (address). The wrapping process involves locking the original asset on its native blockchain, the Bitcoin network, and minting an equivalent amount of the token on the target blockchain, BNB Chain.
Unwrapping BTC: syBTC → BTC
The unwrapping process reverses the wrapping by burning the syBTC on BNB Chain and releasing the equivalent amount of BTC on the Bitcoin network. This ensures that the supply of wrapped tokens always matches the amount of BTC locked, maintaining a 1:1 backing ratio.
On BNB Chain, syBTC can be exchanged for another wrapped BTC token: BTCB and then routed through the Symbiosis protocol using stable tokens or WBTC.
Important: All cross-chain operations involving BTC within the Symbiosis BTC bridge are routed through BNB Chain.
The Symbiosis protocol enables users to exchange BTC with for other digital assets across supported blockchain networks.
Let’s break down how this process works with real examples.
Exchanging BTC for another token through the Symbiosis protocol involves the following steps:
Requesting a Quotation: A user initiates an exchange by specifying the BTC amount, slippage tolerance, destination token, destination chain, and an address on the destination chain.
Receiving a Quotation: The protocol provides a quote detailing the amount of the destination token to be received, estimated fees, and a newly generated BTC address for the user to send their specified amount of BTC.
Triggering the Exchange: The user sends the specified amount of BTC to the provided address, which triggers the cross-chain exchange process with the specified parameters.
Completing the Operation: Once the cross-chain operation is completed, the user receives the destination tokens at the specified address on the destination chain.
Exchanging a token for BTC through the Symbiosis protocol involves the following steps:
Requesting a Quotation: A user initiates an exchange by specifying the token amount, slippage tolerance, BTC as the destination token, the Bitcoin network as the destination chain, and an address on the destination chain.
Receiving a Quotation: The protocol provides a quote detailing the amount of the destination token to be received, and estimated fees.
Triggering the Exchange: The user signs and sends the transaction containing the calldata received on Step 2, which triggers the cross-chain exchange process with the specified parameters.
Completing the Operation: Once the cross-chain operation is completed, the user receives BTC at the specified address on the Bitcoin network.
