BTC.b (Bridged Bitcoin)

BTC.b represents the next evolution in Bitcoin, a fully decentralized, permissionless Bitcoin asset that maintains 1:1 backing with native BTC while offering unprecedented flexibility across multiple blockchain ecosystems. Established in 2022 by Ava Labs, BTC.b had approximately $550M in circulation and deep DeFi integrations, at the time that it was acquired by Lombard (October 2025). For more information about the asset and infrastructure acquisition, please visit this blog post. [https://www.lombard.finance/blog/lombard-acquires-btcb-from-ava-labs]

Unlike existing wrapped Bitcoin products that rely on centralized custodians or require KYC procedures with a centralized exchange, BTC.b operates on Lombard’s transparent, verifiable protocol architecture. Every BTC.b token is backed by native Bitcoin held in a decentralized security framework, verified through multiple independent layers including Chainlink Proof of Reserve, Cubist’s CubeSigner and a consortium of 15 leading digital asset institutions that validate every mint and redeem

The shift from existing wrapped Bitcoin assets to BTC.b is driven by user demand. Users want permissionless, non-custodial and decentralized Bitcoin assets, so their hard-earned Bitcoin is safe onchain and can access opportunities in DeFi. Traditional wrapped assets often create friction through KYC and custody requirements, geographic restrictions, and opaque reserve management. BTC.b eliminates these barriers while maintaining the security standards that institutions require and individuals deserve. The Lombard protocol achieves this through a unique combination of decentralized governance, cryptographic security, and transparent operations that anyone can verify.

Core Architecture

BTC.b leverages Lombard’s multi-layered security model that eliminates single points of failure while maintaining complete transparency. The protocol employs Hardware Security Modules (HSM) for key management through Cubist’s CubeSigner, Byzantine fault-tolerant consensus mechanisms, and dual-layer verification through both Cubist’s Bascule Drawbridge and Chainlink CCIP. This architecture ensures that your Bitcoin remains secure while being fully auditable onchain, no trust required, just verification.

The security consortium includes industry leaders like OKX, Galaxy, DCG, Wintermute, Figment, Kiln, Antpool, F2Pool, and Kraken, providing institutional-grade security without institutional gatekeepers. Every mint & redeem transaction requires majority consensus among validators, creating a robust defense against any potential security threats. This consortium model represents a careful balance between decentralization and operational efficiency. Each member operates independently, with their own infrastructure and security practices, yet they coordinate through the Lombard Ledger to ensure consistent and secure operations.The Lombard Ledger functions as a Byzantine Fault-Tolerant (BFT) Layer 1 network operating with a Proof-of-Authority (PoA) consensus mechanism, purpose-built to record all protocol events transparently onchain and maintain validator integrity.

The technical implementation goes beyond simple multisignature schemes. The protocol implements sophisticated policy engines that restrict what types of transactions can be signed, when they can be executed, and under what conditions. These policies are enforced at the hardware level through HSMs, making it cryptographically impossible for compromised or malicious actors to bypass security controls. Even if multiple consortium members were compromised simultaneously, they would be unable to execute unauthorized transactions due to these hardware-enforced restrictions.

The Journey from Avalanche to Lombard’s Architecture

BTC.b's transition from the original Avalanche Bridge architecture to Lombard's architecture represents a significant technological advancement. The original system, while functional and secure, relied on Intel SGX enclaves and a Warden network for coordination. The migration to Lombard's architecture maintains complete continuity for existing users while dramatically expanding capabilities. Token addresses remain unchanged, existing DeFi integrations continue functioning normally, and users retain full access to their funds throughout the transition. This seamless migration demonstrates the protocol's commitment to user experience and the maturity of the underlying technology.

Seamless Multi-Chain Access

BTC.b will no longer be confined to a single blockchain. The asset will operate natively across Avalanche, Ethereum, Solana, Katana, and MegaETH in its first phase, with more chains added over time. This multi-chain access means you can move your Bitcoin where opportunities exist without being locked into a single ecosystem or dealing with complex bridging procedures.

Each chain implementation is optimized for that specific ecosystem while maintaining consistent security guarantees. On Ethereum and Avalanche, BTC.b will follow the ERC-20 standard, enabling compatibility with the vast ecosystem of DeFi protocols. On Solana, it will leverage the SPL token standard for high-speed, low-cost transactions. The Lombard protocol handles the complexity of cross-chain coordination behind the scenes, presenting users with a simple, unified experience regardless of which chain they're using.

Through Lombard's SDK integration, BTC.b is directly accessible within major platforms including Binance and Bybit wallets, making it easier than ever to mint, manage, and deploy your Bitcoin across DeFi. These integrations go beyond simple wallet support, they enable one-click minting flows, integrated portfolio management, and seamless transitions between centralized and decentralized finance.