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LearnTransparencyBridging Architecture

Bridging Architecture

Lombard enables LBTC and BTC.b to move across blockchains through a dual-verification bridging system. Every cross-chain transfer requires independent approval from both the bridge infrastructure and the Security Consortium, providing a significantly higher security bar than single-layer bridges.

How Bridging Works

When you transfer LBTC or BTC.b from one chain to another, the process involves burning tokens on the source chain and minting equivalent tokens on the destination chain. This burn-and-mint model ensures total supply consistency — the same amount of LBTC or BTC.b exists regardless of how it is distributed across chains.

Dual Verification

Every bridge transfer must be approved by two independent systems before completion:

  1. Bridge Infrastructure — The underlying bridge protocol (Chainlink CCIP, LayerZero, or IBC) validates the transfer through its own consensus mechanism
  2. Security Consortium — The Lombard Consortium independently verifies and co-signs the transfer using its supermajority threshold (10 of 14 members)

Both approvals are required. If either system rejects the transfer, it does not proceed. This means an attacker would need to simultaneously compromise the bridge validators and a supermajority of the Consortium — a far higher bar than compromising either system alone.

Bridge Infrastructure

Lombard integrates with multiple bridging solutions to maximize chain coverage and redundancy.

Chainlink CCIPPrimary
Chainlink Cross-Chain Interoperability Protocol (CCIP) is the primary bridge for EVM-compatible chains. CCIP provides decentralized oracle-based validation, risk management network monitoring, and rate limiting protections. Most LBTC cross-chain transfers use CCIP.
LayerZero
LayerZero provides additional cross-chain messaging capabilities for chains and routes where it offers advantages over CCIP. LayerZero uses configurable security stacks and decentralized verifier networks.
IBC
IBC is used for transfers to Cosmos-ecosystem chains, including the Babylon network. IBC is a protocol-level standard with light client verification, providing strong security guarantees for supported chains.
Native Consortium Bridge
For select routes, Lombard operates a direct bridge verified solely by the Security Consortium. These transfers do not require external bridge infrastructure and rely entirely on the Consortium’s supermajority signing.

LBTC Supported Chains

ChainBridge Method
EthereumNative (origin chain)
BaseChainlink CCIP
BNB ChainChainlink CCIP
BerachainLayerZero
CornLayerZero
EtherlinkLayerZero
KatanaConsortium Bridge
MonadConsortium Bridge
StableConsortium Bridge
SonicLayerZero
SwellLayerZero
TACLayerZero
SolanaLayerZero
StarknetConsortium Bridge
SuiConsortium Bridge
Cosmos HubIBC
Babylon GenesisIBC

BTC.b Supported Chains

BTC.b is available on 3 chains:

ChainBridge Method
MonadConsortium Bridge
StableConsortium Bridge
KatanaConsortium Bridge

Bridge Transfer Flow

A cross-chain LBTC transfer follows these steps:

1Initiation
User submits a bridge transfer request specifying the destination chain and amount
2Source Chain Burn
LBTC tokens are burned on the source chain, reducing supply on that network
3Bridge Validation
The bridge infrastructure (CCIP, LayerZero, or IBC) validates the burn event and generates a cross-chain message
4Consortium Verification
The Security Consortium independently verifies the burn event and co-signs the mint authorization
5Destination Chain Mint
With both approvals confirmed, equivalent LBTC tokens are minted on the destination chain
6Completion
The user receives LBTC on the destination chain at the same exchange rate

Timing

Bridge transfer times vary by route and bridge infrastructure:

  • CCIP transfers — Typically complete within 10-30 minutes depending on source and destination chain finality
  • LayerZero transfers — Similar timeframes to CCIP, varying by chain
  • IBC transfers — Usually complete within a few minutes due to fast finality on Cosmos chains
  • Consortium Bridge transfers — Dependent on Consortium signing speed, typically within minutes

Fees

Bridge transfers may incur gas fees on both the source and destination chains. Bridge protocol fees vary by route and provider. Lombard does not charge additional fees for cross-chain transfers beyond the underlying infrastructure costs.

Security Considerations

  • Dual verification ensures no single system failure can result in unauthorized minting
  • Rate limiting on bridge contracts prevents large-scale attacks even if signatures are compromised
  • Pausable contracts allow the protocol to halt bridge operations if anomalous activity is detected
  • Independent monitoring through Hexagate provides real-time alerts on bridge contract behavior
  • Chainlink CCIP Risk Management Network provides an additional layer of validation on CCIP routes

Next Steps

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