Build Attestation Quorum (2D)

Attestation Setup

Independent builders (n) 12

Quorum threshold (k) 7

Compromised builders 2

Build non-determinism 10%

Round Verdict

—

Largest bucket

0 / 0

Round #

Attacks blocked

Attacks slipped through

How it works

This is a real SHA-256 quorum, computed in your browser with crypto.subtle.digest — not a simulated color roll. Each round builds a canonical "source artifact" string. Every honest builder hashes that exact string; every compromised builder hashes a tampered variant (source + an injected attacker payload) instead. A noisy honest builder hashes the true source plus a random per-build nonce — exactly like a real non-reproducible toolchain (timestamps, path ordering) that yields different bytes for the same logical build. The engine then genuinely tallies which hash string got the most independent votes.

Accept artifact  ⇔  ∃ hash h : count(builders whose real SHA-256 == h) ≥ k
Attack succeeds  ⇔  attacker controls c ≥ k colluding builders
                     (they all hash the same tampered artifact → same hash)

Independent builders (n) — how many separate parties rebuild and genuinely hash the artifact.
Quorum threshold (k) — minimum number of byte-identical real hashes needed before the artifact is trusted. Raising k makes forging a quorum harder but needs more honest, deterministic infrastructure to still agree.
Compromised builders — attackers who all hash the same tampered artifact. Real SHA-256 output differs by a single flipped bit already, so a lone attacker can never match the honest hash by accident — they need real collusion, reaching count ≥ k with the identical tampered bytes, to be wrongly VERIFIED.
Build non-determinism — a genuinely non-reproducible honest builder hashes true-source-plus-random-nonce, producing its own one-off real hash that can't help either side reach quorum (NO QUORUM — release held, not falsely trusted).

Real-world relevance: this is exactly the trust model behind SLSA build provenance, in-toto attestations and Sigstore transparency logs — the mechanism software supply-chain security increasingly relies on so no single compromised build server (or CI account) can silently ship a tampered artifact.

Correct hash (honest) Tampered hash (colluding) Spurious hash (non-determinism)

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