# Architecture

Othentic Stack allows developers to **self-deploy:**

* Customized off-chain service 
* Network of Operators that run and verify arbitrary tasks

Designed to balance scalability, cost-efficiency, and security by leveraging both L1 and L2 layers.

<br>

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## Key Components

### [Smart Contracts](https://docs.othentic.xyz/main/reference/contracts)

The following Smart Contracts are deployed during initialization:

#### Layer 1

The governance layer is deployed on L1 (**Ethereum**) to ensure the highest level of security, integrate with the shared security protocol contracts, and manage critical governance operations.

<table><thead><tr><th width="246.0234375">Contract</th><th>Description</th></tr></thead><tbody><tr><td><a href="../reference/contracts/avs-governance">AVS Governance</a></td><td>Manage operators and governance policies.</td></tr><tr><td><a href="../../reference/contracts/message-handlers#l1-message-handler">L1MessageHandler</a></td><td>Cross-chain messaging contract to broadcast messages to L2 via AVS governance.</td></tr><tr><td><a href="../reference/contracts/treasury">L1AvsTreasury</a></td><td>Manage rewards and handling protocol fee.</td></tr></tbody></table>

#### Layer 2

The task verification layer is deployed on L2 (or Multichain) to minimize operational costs while maintaining availability, high throughput, and low latency. L2s provide a faster and cost-effective environment for handling task submissions and attestations.

<table><thead><tr><th width="250.1484375">Contract</th><th>Description</th></tr></thead><tbody><tr><td><a href="https://github.com/Othentic-Labs/core-contracts/blob/main/src/NetworkManagement/L2/AttestationCenter.sol">AttestationCenter</a> </td><td> Manages verification and historical footprint. </td></tr><tr><td><a href="https://github.com/Othentic-Labs/core-contracts/blob/main/src/NetworkManagement/Common/OBLS.sol">OBLS</a></td><td>Implements Multisig operations and handles BLS signature aggregation.</td></tr><tr><td><a href="https://github.com/Othentic-Labs/core-contracts/blob/main/src/NetworkManagement/L2/L2MessageHandler.sol">L2MessageHandler</a></td><td>Complementary to <code>l1MessageHandler</code> , used for communicating with L1 via Attestation center</td></tr><tr><td><a href="../reference/contracts/treasury">L2AvsTreasury</a></td><td>Manages rewards and handling protocol fee.</td></tr><tr><td><a href="../reference/contracts/internal-task-handler">InternalTaskHandler</a> </td><td>Manages and handles <a href="../learn/advanced-concepts/internal-tasks">Internal Tasks</a>.</td></tr></tbody></table>

***

### [Operator Roles](https://docs.othentic.xyz/main/learn/core-concepts/operator-roles)

The service is distributed over a set of **Operators** who run various roles:

<table><thead><tr><th width="174.0390625">Role</th><th width="498.015625">Responsibility</th></tr></thead><tbody><tr><td><a href="../../learn/core-concepts/operator-roles#performers">Performer</a></td><td>Execute off-chain tasks and generate a <a href="../learn/core-concepts/tasks/proof-of-task">Proof-of-Task</a>.</td></tr><tr><td><a href="../../learn/core-concepts/operator-roles#attesters">Attester</a></td><td>Validate the work of Performers and cast attestations.</td></tr><tr><td><a href="../../learn/core-concepts/operator-roles#aggregators">Aggregator</a></td><td>Collect attestations, aggregate signatures, and submit the final result on-chain.</td></tr><tr><td><a href="../../learn/core-concepts/operator-roles#bootstrap-nodes">Bootstrap Node</a></td><td>Serve as initial points of contact for peers joining the network.</td></tr></tbody></table>

***

### Consensus Engine

The **Othentic Consensus Engine** enables scalable off-chain task execution with full traceability, ultimately delivering validated results on-chain. The Engine enables the execution and validation of arbitrary computational tasks over a distributed set of nodes (referred to as Operators).&#x20;

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The consensus scheme:

{% stepper %}
{% step %}

### Task Execution

When a task is [triggered](https://docs.othentic.xyz/main/learn/core-concepts/tasks/triggers), a [**Performer**](https://docs.othentic.xyz/main/learn/core-concepts/operator-roles#performers) node executes the task, then generates a [Proof-of-Task](https://docs.othentic.xyz/main/learn/core-concepts/tasks/proof-of-task) and submits it to the AVS network.

* The Performer node is selected via a [Leader Election](https://docs.othentic.xyz/main/learn/advanced-concepts/leader-election) mechanism which can be customized by the developer.
* Developers can configure multiple [Task Definitions](https://docs.othentic.xyz/main/learn/core-concepts/tasks/task-definitions) with custom logic based on their use cases.
  {% endstep %}

{% step %}

### Task Validation

[**Attester**](https://docs.othentic.xyz/main/learn/core-concepts/operator-roles#attesters) nodes validate the Proof-of-Task submitted by the Performer, casting BLS-signed attestations.

The weight of their attestation - proportional to the amount of (re)staked assets - is called [Voting Power](https://docs.othentic.xyz/main/learn/core-concepts/voting-power), and determines the influence of an Attester over the consensus process.&#x20;
{% endstep %}

{% step %}

### Aggregation

Finally, an [**Aggregator**](https://docs.othentic.xyz/main/learn/core-concepts/operator-roles#aggregators) node collects all valid attestations cast by operators and monitors for the quorum:

* <mark style="color:green;">**Task Approval**</mark>: >⅔ of total network voting power attests **"valid"**
* <mark style="color:red;">**Task Rejection**</mark><mark style="color:red;">:</mark> >⅓ of total network voting power attests **"invalid"**

Once quorum is reached, the Aggregator aggregates all the attestations and submits an on-chain transaction to the AttestationCenter contract to finalize the task.
{% endstep %}

{% step %}

### Verification and Finality

The [**AttestationCenter**](https://docs.othentic.xyz/main/reference/contracts/attestation-center) smart contract plays a key role in verifying the off-chain execution and maintaining a transparent on-chain record of all activities.

When the [`submitTask`](https://docs.othentic.xyz/main/reference/contracts/attestation-center#task-submission) transaction is executed, the AttestationCenter contract verifies the aggregated signature submitted by the Aggregator, and if valid, the task is successfully processed by the contract and finalized onchain.
{% endstep %}
{% endstepper %}

***

## Business Logic&#x20;

Developers implement two primary services:

### [Execution Service](https://docs.othentic.xyz/main/learn/core-concepts/execution-service)

The Execution Service runs on **Performer nodes** and is responsible for **executing Tasks** and generating a [**Proof-of-Task**](https://docs.othentic.xyz/main/learn/core-concepts/tasks/proof-of-task).

This service is responsible for:

* Task execution&#x20;
* Proof generation
* Submitting the task via the [`sendTask`](https://github.com/Othentic-Labs/simple-price-oracle-avs-example/blob/main/Execution_Service/src/dal.service.js#L22) JSON-RPC call to the AVS network

A Proof-of-Task could be the result of a calculation, a ZK proof, the CID of a JSON on IPFS, etc.

Task Validation implementation should be able to use this proof to attest to task validity.

### [Validation Service](https://docs.othentic.xyz/main/learn/core-concepts/validation-service)

The Validation Service runs on **Attester nodes** and is responsible for **verifying the validity** of a Task execution submitted by a Performer.

The Attester:

* Receives the task
* Uses the Validation Service API endpoint at `/task/validate` to verify the `proofOfTask`

This is similar to how the Consensus Client communicates with the Execution Client in Ethereum.

***

## [Peer-to-peer Networking](https://docs.othentic.xyz/main/learn/advanced-concepts/p2p-networking)

The peer-to-peer layer is responsible for establishing and maintaining a secure and efficient communication channel between network nodes, including **peer discovery** and **message propagation**.

The layer utilizes signature-based authentication to manage peer connectivity and handshaking, ensuring that only valid peers are able to communicate.

#### Additional Features

* [Custom messaging](https://docs.othentic.xyz/main/user-guide/network-management/custom-messaging)
* [Auth layer](https://docs.othentic.xyz/main/learn/advanced-concepts/p2p-networking/auth-layer)
* [Metrics and monitoring](https://docs.othentic.xyz/main/learn/advanced-concepts/p2p-networking/metrics-and-monitoring)
* [Persistent storage](https://docs.othentic.xyz/main/learn/advanced-concepts/p2p-networking/persistent-storage)