Borrowing it
Nothing to install: this file belongs to sparq-org/sparq. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/sparq-org/sparq/main/.claude/skills/mpc-protocols/SKILL.mdgit clone --depth 1 https://github.com/sparq-org/sparqWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/sparq-org/sparq/mpc-protocols)<a href="https://agentmods.dev/skills/sparq-org/sparq/mpc-protocols"><img src="https://agentmods.dev/badge/skills/sparq-org/sparq/mpc-protocols.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00155 | $0.02084 |
| Opus 5 | $0.00077 | $0.01042 |
| Sonnet 5 | $0.00031 | $0.00417 |
| Haiku 4.5 | $0.00015 | $0.00208 |
Grade A, and why
mpc-protocols scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MPC protocols for federated SPARQL (RQ2)
[OPUS-4.8] Design-for-review (Fable unavailable — flag for re-review). Ground
truth: research/mpc-zkp-research-and-architecture.md and the sparq-mpc crate
(crates/sparq-mpc/{src/lib.rs,PLAN.md}, currently a Milestone-0 scaffold). Every
crypto claim must trace to a citation in the architecture doc — do not invent.
The frame: four guarantees, kept DISTINCT
The single most common error in this space is conflating guarantees. Keep them separate at all times:
- (A) Confidentiality — no party learns another's inputs.
- (B) Computation correctness — the output is the right answer.
- (C) Input authentication — "derived from attested sources": the data is
issuer-signed under a key in the disclosed key-set
K. - (D) Malicious security — guarantees hold against actively cheating parties, not just honest-but-curious ones.
Three pitfalls encoded as hard assumptions: commitment ≠ attestation (proving over committed data says nothing about who signed it — needs a CP-SNARK/Dutta link); confidentiality ≠ correctness (a "no party learns X" system can still return wrong answers — most graph-MPC papers only deliver A); honest-majority ≠ malicious-against-N−1.
MPC primitive families (pick by network + trust model)
- Secret sharing. Honest-majority 3PC replicated SS is the perf sweet spot (1 element/mult-gate; ~2× for malicious) but assumes ≥2-of-3 non-colluding compute parties — a strong assumption for a hostile federation. Dishonest-majority malicious (SPDZ / MASCOT / Overdrive) is the realistic cross-org model but pays expensive input-independent preprocessing usually excluded from headline numbers.
- Garbled circuits (Yao / BMR). Constant-round → wins on WAN (the federated setting). Secret-sharing is round-per-circuit-depth → wins on LAN. Network model dictates protocol.
- PSI for private joins. VOLE-PSI: 2²⁰ elements, malicious, 6.2 s. But it is two-party, single equi-join, key-on-key — it does not compose for free into a multi-pattern SPARQL BGP or non-key / unbound-variable joins.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 130 lines · 155 tokens per session scan A a37b4fe6c210
mpc-protocols is a skill published in the GitHub repository sparq-org/sparq (10 stars, last pushed yesterday), licensed MIT. It adds 155 tokens to every session and 2,084 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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