ZKSwap (Bitcoin) Mainnet will initially adopt the Schnorr multisignature and Taproot solution, and will later transition to ZKByte

After the Taproot upgrade on the Bitcoin mainnet, it became possible to construct m-n multisignature Taproot accounts using Schnorr signature technology. By constructing a special Tapscript, it is possible to implement Schnorr-based threshold signatures.

Any Tapscript can be understood as a special script that exists with multiple conditions and can be unlocked according to each condition. Each branch’s unlocking script is actually a leaf node of the Merkleized Abstract Syntax Tree (MAST). Clearly, by treating the different possible outcomes of Schnorr signatures as independent leaf nodes, an m-n multisignature wallet can be implemented.

Specifically, generating such a Tapscript requires multiple parties to construct the script off-chain. Taking a 2–3 multisignature as an example, participants must first construct multiple sets of possible Schnorr multisignatures off-chain. For instance, through MuSig2, three participants A, B, and C generate Sig1(A,B), Sig2(B,C), and Sig3(A,C) respectively. Subsequently, these three generated Schnorr signatures Sig1, Sig2, Sig3 are placed in different leaf nodes and combined with OP_CHECKSIG. Finally, by using the leaf nodes, the final Merkle tree root is generated, completing a Taproot multisignature wallet as shown in the diagram.

The advantages of ZKSwap (Bitcoin) adopting Schnorr signatures are clear, enabling native m-n multisignature capabilities along with other benefits of native Schnorr multisignature, such as privacy protection and reduced space usage. At the same time, it greatly expands the number of fragments a multisignature wallet can have, theoretically allowing the construction of more decentralized cross-chain bridges to further increase the security of the multisignature scheme.

Currently, the multisignature scheme for ZKSwap (Bitcoin) is only a temporary transitional solution. In the future, the ZKSwap (Bitcoin) mainnet will adopt a Bitcoin Layer2 expansion solution based on ZK and BitVm, called ZKByte. This will not only enhance the security and integrity of the Bitcoin Layer2 network but also improve speed, efficiency, and security. The design framework of ZKByte is to establish a custom Layer2 network for the Bitcoin blockchain. The Bitcoin Layer2 network aims to meet the growing demand within the Bitcoin ecosystem for faster, more efficient transactions. By offloading some transaction processing tasks from the mainnet, it aims to alleviate congestion on the Bitcoin mainnet and significantly reduce the time required for transaction confirmations.

Given the inherent limitations of Bitcoin Virtual Machine (VM) computing power, our design uses BitVM, which demonstrates the potential for executing smart contracts between two layers of networks. Utilizing challenge and response schemes, BitVM presents a new method for programmability of the Bitcoin network, breaking traditional limitations.

To enhance the security and integrity of the Bitcoin Layer2 network, the design integrates zero-knowledge proof (ZK) technology for state verification. These advanced cryptographic technologies allow the Bitcoin mainnet to effectively verify the state of the Layer2 network without compromising the privacy and confidentiality of underlying transactions. Zero-knowledge proofs can verify information without disclosing the specifics of transactions, thus ensuring the integrity of the Layer2 network while protecting privacy.

Overall, the design aims to enhance the scalability, speed, and efficiency of the Bitcoin network through a Layer2 network, smart contract execution using BitVM, and state verification integrating zero-knowledge proof technology, while maintaining the privacy and security of underlying transactions.

ZKBase Team