For the first time in history, the infrastructure of a live onchain asset has been acquired. Lombard has acquired BTC.b, the leading Bitcoin asset on Avalanche with approximately $550 million in circulation, along with its infrastructure, to bring a new BTC asset to market. This historic deal transforms BTC.b from a single-chain asset into a multi-chain standard for permissionless Bitcoin, fully integrated and operating exclusively on Lombard's protocol infrastructure as they accelerate Bitcoin Capital Markets onchain.
Bridge Migration
As part of Avalanche’s transition of BTC.b infrastructure and related assets to the Lombard Protocol, Cubist is providing the secure key management and minting/withdrawal operations layers that underpin the new system’s design. BTC.b will first transition to the same trusted architecture as LBTC, before Lombard coordinates its distribution and integration across select chains and leading DeFi protocols. In its initial phase, BTC.b will expand beyond Avalanche to Ethereum mainnet, Katana, MegaETH and Solana. Migration is underway with launch expected in Q4.
New Security Model
Under the new model, Lombard assumes responsibility for cross-chain bridging and security, implementing multiple independent security layers with decentralized validation. The new architecture consists of a 15-member Security Consortium with BFT consensus, HSM-backed key management powered by CubeSigner, dual-layer verification through Cubist Bascule and Chainlink CCIP, and the Byzantine fault-tolerant Lombard Ledger for traceability and transparency.
With Lombard, BTC.b operations move to a trust-minimized, multi-layered security model designed for institutional scale and cross-chain expansion.
Layer 1: Decentralized Validation
The Security Consortium replaces the Warden network with 15 independent digital asset institutions including OKX, Galaxy, DCG, Wintermute, Figment, Kiln, Antpool, F2Pool, and Kraken. This Proof-of-Authority network operates the Lombard Ledger, a Byzantine fault-tolerant consensus layer that records all protocol operations transparently onchain.
Every transaction requires majority consensus among validators, eliminating single points of failure.
Layer 2: HSM-Backed Key Management
In the new security model, the Security Consortium members use Cubist's CubeSigner platform to manage keys and sign transactions. Unlike in the previous model, where SGX enclaves were used to reconstruct keys and coordinate Warden approvals, Consortium members sign transactions but never have access to secret key material. Instead, keys remain in Cubist's secure hardware, which combines FIPS 140 HSMs and Nitro Enclaves to provide enhanced security. Moreover, these keys are further locked down by multiple security policies, which restrict the Consortium members to only signing specific types of transactions (e.g., mints backed by deposits) approved by a majority of the parties.
Layer 3: Governance Policies
Multiple security policies govern key usage:
- Timelocks: Enforced delays for sensitive operations
- Multi-Party Approval (MPA): Multiple consortium members must approve every transaction and policy change
- Transaction restrictions: Keys can only sign specific pre-approved transaction types
Layer 4: Independent Bridge Verification
Two independent systems verify all operations:
- Cubist's Bascule Drawbridge: Verifies collateral consistency across Bitcoin and destination chains (Avalanche C-Chain, Ethereum, etc.)
- Chainlink CCIP: Verifies collateral across chains where BTC.b is bridged, by providing secure cross-chain messaging and real-time Proof of Reserve verification
This dual-verification approach ensures 1:1 backing through independent auditing layers.
Operating exclusively on Lombard’s transparent, verifiable protocol architecture, BTC.b will be a next-generation Bitcoin asset built for the decentralized economy—permissionless, non-custodial, and secure. BTC.b will bring institutional-grade security to onchain Bitcoin without the institutional gatekeepers and will continue serving as Avalanche's primary Bitcoin bridge while expanding to become a truly multi-chain Bitcoin asset.
This is an excerpt from Lombard's announcement, which describes the infrastructure transition and roadmap in detail.
