ZCG Application — PrivateSync: Privacy-Preserving Light Client Sync Infrastructure (feedback wanted)

Community Grants
1

Hi all,

I’ve submitted a ZCG grant application and I’m posting it here for community
input, as required: Grant Application - PrivateSync: Privacy-Preserving Light Client Sync Infrastructure for Zcash · Issue #549 · ZcashCommunityGrants/zcashcommunitygrants · GitHub

The problem: Zashi/Ywallet sync through lightwalletd servers, and that
sync leaks the user’s IP address and which compact blocks the wallet
downloads — a metadata trail that can deanonymize otherwise shielded
activity. lightwalletd’s own wallet-app threat model documents these
limitations, and ZCG’s open RFP for lightwalletd infrastructure asks for a
multi-operator solution.

The proposal: a three-tier privacy stack for light client sync, aligned
with upstream work already in flight (librustzcash #2665, SDK #1741):

  • Tier 1 — Tor onion sync for lightwalletd (ships first)
  • Tier 2 — Tor + multi-server PIR, where no single sync node learns which
    block you requested (information-theoretic, per-server privacy)
  • Deployment: 3–5 independently operated testnet nodes + a runbook so more
    operators can join — the multi-team model the RFP calls for

Ask: $27,000 over 8 months, paid per milestone, no upfront.

Evidence base (everything is public):

I’d genuinely value critique before ZCG reviews it — especially on:

  1. the PIR bandwidth assumptions vs real compact-block sizes,
  2. the node-operator recruitment plan,
  3. whether Tier 1 (Tor-only) should just be the default end-state.

Thanks for reading. :shield:

2

Ywallet has been discontinued for several years, superseded under the name “ZWallet”, which in turn was discontinued AGAIN at Ironwood (July) and is now superseded by Zkool2, made by our very own @hanh , and it supports Tor natively via an Arti client built-in. Arti was also funded by ZCG.

Zashi also integrated Tor via Arti in Zashi 2.1. Zashi isn’t even called Zashi anymore! It’s ZODL wallet!

It gets better. Private information retrieval for compact blocks was like, JUST announced like 2-3 weeks ago by Vizor Wallet. And maybe Zakura too, I don’t remember clearly.

This is very characteristic of using an LLM to generate the application, btw, due to knowledge cutoffs. Just saying.

3

I AM SORRY BUT THIS IS TOO FUNNY TO PASS UP

image
image1230×1126 117 KB

Source: Delete TEAM.md · sarinsk629-blip/Zcash_privacy-preserving-light-client-sync-proposal@553ba1c · GitHub

(BTW this was the only human made change in the entire repo; the other changes were made by agents)

1 Like