Technical Overview & Security

How it works

The Tensorplex bridge facilitates the cross-chain transfer of the TAO token between the Bittensor Network and Ethereum mainnet through a network of relayers.

Relayer

The bridge relayer plays a crucial role in enabling such transfers:

• Monitoring: Relayers constantly monitor both blockchains for deposit events at the bridge addresses.

• Cross-Chain Communication: When a deposit is detected, relayers initiate the process to mint or release tokens on the destination chain.

• Transaction Verification: Relayers verify the validity of the deposit transaction before proceeding with the mint or release on the other chain.

• Consensus: Multiple relayers work together to ensure agreement on the validity and details of each transfer, enhancing security and reducing the risk of a single point of failure.

• Execution: Once consensus is reached, relayers interact with the smart contracts on the destination chain to complete the transfer.

Multi-Relayer Consensus Mechanism

The bridge employs a multiple relayer setup to eliminate single points of failure:

• A minimum of three relayers are active at any given time.

• For each bridging transfer to be approved, at least two out of the three relayers must reach consensus.

• The 2-of-3 quorum ensures:

  • Protection against potential malicious actions by a single relayer

  • Redundancy in case one relayer fails or is compromised

  • Increased reliability and uptime of the bridging service

Security

Ensuring the security of the bridge is our top priority. Beyond implementing a robust framework that includes a trust-minimised multi-relayer setup and independent hardened infrastructure, the team has also worked with partners to perform audits across the entire stack of the developed technology, as well as introducing rate-limiting measures.

Audits

To ensure the highest standards of security, various parts of the bridge has undergone rigorous auditing by experienced and reputable audit firms:

• Quantstamp: A comprehensive review of the bridge's smart contracts and overall architecture.

• Zellic: A security assessment of the bridge's relayer infrastructure, focusing on potential vulnerabilities on the relayer and the hosting infrastructure.

These audits have helped to identify and address non-critical potential security issues before they can be exploited, and have provided feedback on enhancing the bridge's overall safety.

Rate Limiting Measures

To protect against potential attacks or unexpected large-scale transfers, the bridge employs a rate-limiting mechanism as a final line of defence.

• Inflow Limits: Restrictions on the amount of TAO that can be bridged from Bittensor to Ethereum within a specified timeframe.

• Outflow Limits: Similar restrictions on the amount of TAO that can be bridged from Ethereum back to Bittensor.

These limits will be gradually increased to accommodate growing demand while maintaining optimal security.