82 lines
3.9 KiB
Markdown
82 lines
3.9 KiB
Markdown
# Mixnet v2 Simulation
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* [How to Run](#how-to-run)
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+ [Time in simulation](#time-in-simulation)
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* [Mixnet Functionalities](#mixnet-functionalities)
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* [Adversary Models](#adversary-models)
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## How to Run
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First, make sure that all dependencies specified in the `requirements.txt` in the project root.
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Then, configure parameters in the [`config.yaml`](./config.yaml), and run the following command:
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```bash
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python main.py --config ./config.yaml
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```
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The simulation runs during a specified duration, prints the results to the console, and show some plots.
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### Time in simulation
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The simulation is implemented based on [SimPy](https://simpy.readthedocs.io/en/latest/) which is discrete-event simulation framework.
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All events are processed sequentially by a single thread.
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However, multiple parallel events, which should be processed at the same time, can be also simulated by scheduling them at the same "time".
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The simulation has the virtual time concept, which doesn't have the same scale as the real time.
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If the event A is scheduled to happen at time 10, and the event B is scheduled to happen at time 11,
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the simulation guarantees that the event B happens only after the event A happens.
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But, it doesn't mean that the event B happens exactly 1 second after the event A. It will be much shorter.
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If two events are scheduled at the same time (e.g. 10), the simulation processes the one that is scheduled first and the other one next (FIFO).
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But, it is guarantees that those two event are processed before the events scheduled at time 11+.
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Using this virtual time, complex distributed systems can be simulated in a simple way without worrying about the real-time synchronization.
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For more details, please see the [Time and Scheduling](https://simpy.readthedocs.io/en/latest/topical_guides/time_and_scheduling.html#what-is-time) section in the SimPy documentation.
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## Mixnet Functionalities
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- Modified Sphinx
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- [x] Without encryption
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- [ ] With encryption
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- P2P Broadcasting
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- [x] Naive 1-to-all
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- [ ] More realistic broadcasting (e.g. gossipsub)
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- [x] Sending a real message to the mixnet at the promised interval
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- Each node has its own probability of sending a real message at each interval.
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- [x] Cover traffic
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- All nodes have the same probability of sending a cover message at each interval.
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- [x] Forwarding messages through mixes, and then broadcasting messages to all nodes if the message is real.
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- Mix delays
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- [x] Naive random delays
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- [ ] More sophisticated delays (e.g. Poisson) if necessary
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## Performance Measurements
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- [ ] Bandwidth Usage
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- DRAFT with the naive 1-to-all broadcasting
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- Should be measured with realistic parameters and P2P gossiping.
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## [Adversary Models](https://www.notion.so/Mixnet-v2-Proof-of-Concept-102d0563e75345a3a6f1c11791fbd746?pvs=4#c5ffa49486ce47ed81d25028bc0d9d40)
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- [x] Inspecting message sizes to analyze how far each message has traveled since emitted by the original sender.
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- Currently, all messages have the same size (including messages broadcasted after being fully unwrapped). Thus, the adversary can learn nothing.
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```
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message_size
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count 1806.0
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mean 1937.0
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std 0.0
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min 1937.0
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25% 1937.0
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50% 1937.0
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75% 1937.0
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max 1937.0
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```
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- Identifying nodes emitting messages around the promised interval.
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- [x] As the GPA
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- [ ] With partial visibility
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- [ ] Quantifying how much the expected frequent senders are anonymized by cover traffic
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- [ ] Correlating senders-receivers based on timing
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- DRAFT
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- This can indicate whether a certain node has extremely few messages being mixed in the node.
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But, I don't think this is the best way to analyze the correlation.
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I think we need to try to simulate the actual timing attack.
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- [ ] Active attacks |