The median-4% invariant: a manipulation-robust price without an oracle

Why BlazePhoenix V2 defends pricing with a trimmed median across sources and a 4% robustness band instead of a single quote — resistant to one poisoned pool. Specified, pre-audit.

Known formally as The Median-4% Invariant in the BlazePhoenix whitepaper.

BlazePhoenix Engineering · updated 2026-08-05 · 7 min · written from the deployed bytecode

By Mitra (@Sigmacrit) — anonymous developer of the BlazePhoenix protocol. The code is the résumé.

BlazePhoenix V2 is pre-deployment and under audit; this describes the designed mechanism. A single spot price is trivial to poison: move one thin pool and the number moves. The classic fix is an external oracle, which reintroduces a trusted third party. V2 instead takes a median across independent on-chain sources and accepts a value only if it sits within a bounded robustness band.

Why the median, and why 4%

The median is the order statistic that a minority of manipulated inputs cannot drag: to move a median you must corrupt half the sample, not one member of it. The 4% band is the tolerance the design allows between the accepted price and the cluster of honest sources; a source outside the band is treated as an outlier, not as truth. The effect is oracle-grade robustness computed entirely on chain, with no feed to trust or bribe.

Do not trust this page — reproduce it

Every claim above is checkable against the chain. Start here:

Reproduce the idea off-chain: take five pool prices for a pair, poison one by 50%, and confirm the median barely moves while the mean does
Cite this article

Licensed CC BY 4.0 — quote, translate and reuse freely, including commercially, with attribution and a link. Copy a ready-made citation:

BlazePhoenix (2026). The median-4% invariant: a manipulation-robust price without an oracle. BlazePhoenix Engineering. https://blazephoenix.xyz/learn/median-4-percent-invariant
@misc{blazephoenix_median_4_percent_invariant,
  title  = {The median-4% invariant: a manipulation-robust price without an oracle},
  author = {BlazePhoenix},
  year   = {2026},
  url    = {https://blazephoenix.xyz/learn/median-4-percent-invariant},
  note   = {Accessed: reproduce the claim with the command above}
}

Writing an answer, a wiki entry or a paper? The claim above is reproducible against the chain before you quote it — which is the only sound basis for citing a technical source at all.

Contracts are verified on every chain we deploy to — addresses in the protocol manifest. Deeper formal treatment: the whitepaper (PDF). Standards cited: HTTPS://ARXIV.ORG/ABS/2506.22142 · HTTPS://ARXIV.ORG/ABS/2410.07893

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