What is the Role of the Avalanche Bridge™ Nodes?

The Avalanche Bridge™ comprises two primary components:

1. The SGX application (secure enclave).
2. Bridge Nodes (third-party indexers and verifiers).

Bridge Nodes index transactions on the Avalanche® and Ethereum blockchains, submitting eligible transfers to the enclave for processing.

Core Functions of Bridge Nodes

Transaction Eligibility Criteria

Bridge Nodes identify:

• Supported ERC20 transfers to the designated Ethereum wallet.
• Successful calls to the unwrap function on Avalanche Bridge tokens.

Key Requirements:

• Transferred tokens must cover gas fees + a $5 buffer (configurable).
• Transactions below this threshold are not indexed.

👉 Explore how Bridge Nodes enhance cross-chain efficiency

Security & Consensus Mechanism

Multi-Node Validation

• The SGX enclave requires 6 of 8 Bridge Nodes to submit identical transactions before signing cross-chain transfers.
• Each node communicates directly with the enclave via encrypted TLS channels.

Access Controls

• Enclave and Bridge Nodes whitelist each other’s IPs.
• All communications use TLS + HMAC signatures for integrity.

Intel SGX Application Architecture

Trusted vs. Untrusted Components

Remote Attestation

• Bridge Nodes attest the enclave’s validity on startup.
• Public JSON files store attestation reports for transparency.

👉 Learn about SGX’s role in blockchain security

Bridge Node Responsibilities

1. Indexing:

   • Tracks Avalanche/Ethereum transactions via AvalancheGo and Geth nodes.

2. Secret Sharing:

   • Holds encrypted Shamir secret shares to reconstruct the master key (requires 6/8 nodes).

3. Frontend Sync:

   • Hosts JSON files with bridge settings; frontend disables if node reports mismatch.

FAQs

❓ How do Bridge Nodes prevent ineligible transactions?

Bridge Nodes enforce minimum transfer values (gas costs + buffer) before indexing.

❓ What happens if Bridge Nodes disagree on a transaction?

The SGX enclave only processes transactions with 6/8 consensus.

❓ How are private keys secured?

Keys are derived from a master secret split via Shamir’s method; no single node holds full access.

Upcoming Changes & Sunset of AEB

• AEB Sunset: Legacy bridge disabled after August 9; funds moved to Avalanche Bridge Wallet.
• New Features: Post-sunset, enclave updates will enable token swaps via Bridge contracts.

Why Choose Avalanche Bridge?

• Speed: Single-action transfers.
• Cost: Minimal on-chain requirements.
• Security: SGX + multi-node consensus.

For details, read: