tBTC is a decentralized, permissionless Bitcoin bridge developed by the Threshold Network to bring Bitcoin (BTC) liquidity to Ethereum and other EVM-compatible networks. It operates as a trustlessly Bitcoin-backed ERC-20 token, enabling participation in Ethereum's decentralized finance (DeFi) ecosystem without relying on centralized custodians.
tBTC functions by allowing users to deposit Bitcoin into the tBTC bridge, which is secured through threshold cryptography. The deposited Bitcoin is managed by a randomly selected group of node operators from the Threshold Network. These operators require a majority agreement before performing any actions with the Bitcoin, and their selection rotates weekly to prevent malicious control. Users can then mint tBTC, an ERC-20 token fully backed 1:1 by the deposited Bitcoin, to use within Ethereum's DeFi applications. The process involves generating Bitcoin wallets, deposit sweeping, and optimistic minting to ensure security and efficiency.
tBTC has several potential use cases, particularly in the DeFi space:
tBTC was developed by the Threshold Network following a merger between NuCypher and Keep. It has evolved from its initial version, tBTC v1, which used an over-collateralized model, to the more efficient tBTC v2. This latest version employs probabilistic guarantees and a distributed node selection to enhance scalability and security. Key milestones include security audits, integration with Layer 2 networks, and a focus on cross-chain functionality. Noteworthy partnerships, such as with Wormhole, have bolstered its market presence and expanded its usage across multiple blockchain ecosystems.