# 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 <a href="#multi-relayer-consensus-mechanism" id="multi-relayer-consensus-mechanism"></a>

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.&#x20;

### 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.&#x20;

### Rate Limiting Measures <a href="#rate-limiting-measures" id="rate-limiting-measures"></a>

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.