Bitlayer is a Bitcoin-based Layer 2 solution that aims to enhance Bitcoin’s capabilities while preserving its security. It strives to combine Bitcoin-equivalent security with Turing-complete programmability—a rare combination for Bitcoin infrastructure .
Key Features & Architecture
Built on BitVM Paradigm
Bitlayer leverages the BitVM2 and BitVM paradigm, which blends zero-knowledge and optimistic fraud proofs, enabling Turing-complete smart contracts on Bitcoin .
EVM Compatibility
It supports the Ethereum Virtual Machine (EVM), allowing developers to easily port Ethereum-based dApps to Bitlayer .
Security through Fraud-Proof Rollup Model
Bitlayer uses a hybrid approach: state transitions are assumed valid unless challenged during a designated dispute window (e.g., 7 days). If an incorrect claim is posted, a challenger can trigger a fraud-proof mechanism, slashing the dishonest operator .
Technical Architecture & Rollup System
From the whitepaper and documentation:
Rollup Infrastructure
Bitlayer’s rollup aggregates L2 transactions and periodically submits state roots and proofs to Bitcoin’s Layer 1. The proofs are presumed valid unless disputed .
Fraud-Game Protocol (BitVM2)
A challenge/response system is in place where operators submit state claims, and watchers can dispute validity via a recursive challenge game using Bitcoin script and zero-knowledge proofs .
Dual Finality Model
Soft Finality: Transactions finalize quickly on L2.
Hard Finality: Security equivalent to Bitcoin’s L1 finality once state roots are confirmed .
Validator & Operator Roles
Bitlayer employs a PoS-based validator set. A rotating operator submits rollup state claims, while watchers and attesters verify correctness and can initiate fraud challenges .
Status & Present-Day Developments
Bitlayer PoS (Mainnet V1)
The Proof-of-Stake sidechain, also called Bitlayer PoS (Mainnet-V1), is already live as of early April 2024 .
Bitlayer Rollup (Mainnet V2)
The next-generation rollup (Bitlayer V2) is under active development. Testnet versions, including the BitVM bridge, are already available and expected to evolve into a full rollup rollout .
Summary Table
FeatureDescriptionSecurity ModelBitcoin-equivalent via fraud proofs and zero-knowledge verificationProgrammabilityTuring-complete smart contracts via BitVM paradigmCompatibilityEVM support enables seamless dApp migrationCurrent StatusBitlayer PoS (V1) live; Rollup (V2) in testnet phaseChallenge Mechanism7-day dispute window with depositor slashing on invalid claimsArchitectureDecentralized PoS validators, rotating operator, watchers, attesters
In a Nutshell
bitlayer.org is central to the Bitlayer project, which is forging a path for scalable, programmable, and secure Bitcoin-based rollups. With BitVM, fraud proofs, and EVM support, it's positioning Bitcoin as a viable platform for DeFi and smart contracts in ways previously reserved for other blockchains.
