https://github.com/timyiu478/dolev-strong-protocol

A State Machine Replication built on top of Dolev-Strong Authenticated Broadcast Protocol
https://github.com/timyiu478/dolev-strong-protocol

byzantine-broadcast consensus distributed-systems pki protocol simulation state-machine-replication synchrony

Last synced: 7 months ago
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A State Machine Replication built on top of Dolev-Strong Authenticated Broadcast Protocol

• Host: GitHub
• URL: https://github.com/timyiu478/dolev-strong-protocol
• Owner: timyiu478
• License: mit
• Created: 2025-08-24T09:16:19.000Z (9 months ago)
• Default Branch: main
• Last Pushed: 2025-09-06T04:27:33.000Z (9 months ago)
• Last Synced: 2025-09-06T05:37:27.305Z (9 months ago)
• Topics: byzantine-broadcast, consensus, distributed-systems, pki, protocol, simulation, state-machine-replication, synchrony
• Language: Python
• Homepage:
• Size: 28.7 MB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: history/0.txt
  • License: LICENSE

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README

          
## About

This repository shares my implementation of a toy state machine replication built on top of the dolev-strong protocol for educational purposes.

---

## Overall Design

![](assets/overall_design.png)

---

## Repo Structure

- **src/**: Contains the main source code for the protocol and state machine.

- **main.py**: Run this script to start a protocol simulation.

- **tests/**: Includes test cases for validating protocol correctness.

- **assets/** & **recording/**: Visual resources for documentation and examples.

---

## Example Run

### Understand The Output

The program will output the register value and history(append-only log) of each honest node for each dolev-strong protocol cycle(or epoch). We should see that all honest nodes have the same register value and history at the end of each cycle.

```bash

Node 0's register value is 0

Node 0's history is []

Node 3's register value is 0

Node 3's history is []

```

### Attack Strategies

- non-sender: does not participate in the protocol

- sender: 

    - sometime, send value $v1$ to half of the non-senders and send value $v2$ to another half of the non-senders

    - sometime, it follows the protocol correctly (it acts as an honest node)

### Case 1: 2 Honest Nodes, 2 Faulty Nodes, 1 is the sender and 1 is the non-sender, fixed leader mode

![2_f_n_1_sender.gif](recording/2_faulty_node_1_sender_1_non_sender.gif)

### Case 2: 2 Honest Nodes, 2 Faulty Nodes, both are non-senders, fixed leader mode

![2_f_n_both_non_senders.gif](recording/2_faulty_node_2_non_senders.gif)

### Case 3: 2 Honest Nodes, 2 Faulty Nodes, round-robin leader election mode

![rr_leader_election.gif](recording/round_robin_leader_election.gif)

Occasionally, the register values of honest nodes may differ, but their histories remain identical because the executor has not yet applied the latest record.

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## Dolev-Strong protocol

The dolev-Strong protocol is an authenticated protocol for solving broadcast, against any adversary controlling *t