> ## Documentation Index
> Fetch the complete documentation index at: https://docs.decdn.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Privacy analysis

> An accountability-first privacy design — a four-tier adversary model, an inventory of privacy surfaces, and the four specified mitigations.

## Decision

Privacy is treated as an **accountability-first** design: probes are public, on-chain channels enable disputes, gossip enables discovery. Most privacy surfaces are accepted as inherent. Four concrete mitigations are specified below; deeper techniques (dummy probes, channel mixing) are future work.

## Adversary model (four tiers)

| Tier                        | Example adversary                                   | What they can observe                                                  |
| --------------------------- | --------------------------------------------------- | ---------------------------------------------------------------------- |
| **Passive observer**        | On-path network middlebox                           | QUIC metadata (IPs, SNI unless ECH is deployed), timing, volume        |
| **Active participant**      | Malicious node or client                            | Probes, gossip activity, payment channel open/close                    |
| **Infrastructure operator** | L2 RPC provider, relay host                         | On-chain events at read time; relay endpoints see encrypted QUIC flows |
| **Compromised endpoint**    | Malicious origin or content-provider infrastructure | Plaintext bytes, client subscription identity                          |

## Privacy surfaces

The protocol inventories its distinct privacy surfaces with explicit dispositions (accept or mitigate). Highlights:

* **On-chain settlement volume leakage.** Anyone can read channel open/close amounts on-chain. Accepted: disputes require public channel state.
* **Signed protocol messages as non-repudiable content commitments.** A node that signs an availability response has provably committed to serving that hash. Accepted: the same signature is what enables on-chain accountability.
* **Probe traffic.** Who probes what is visible to the probed node. Accepted: selection depends on probing; fully private probing would require PIR at O(log N) blow-up.

## Mitigations

1. **Client NodeId rotation.** Clients rotate NodeIds on session boundaries to break linkability across subscription sessions.
2. **Bounded availability hints.** Probe responses include only a small number of additional cached hashes, lowering the precision of per-node content fingerprinting.
3. **Client key encryption via platform keychain.** Clients store Ethereum keys in macOS Keychain, Windows Credential Manager, or Gnome Keyring — not plaintext files.
4. **Multi-source RPC.** Clients and nodes use multiple independent RPC providers to reduce single-vendor deanonymization surface.

## Future work

* **Dummy probes.** Inject cover-traffic probes to obscure real content interest. Unresolved cost/benefit.
* **Payment channel mixing.** Route settlements through a mixing contract. Regulatory complexity.

## Scope clarifications

* **Content plaintext** is a content-provider concern. If sensitivity requires it, the content provider encrypts before publishing.
* **Client IP addresses** are visible to peers. Tor-style relaying is out of scope — adding a layer of indirection conflicts with the pay-per-byte accountability model.