EchoCert Midnight

EchoCert on Midnight is a zero-knowledge selective disclosure demo: prove that one field of your diploma is real, reveal nothing else, and leave no trace that lets anyone link two proofs to the same holder. It was built for the MLH Midnight Hackathon (2026-08-28 → 30) as a privacy upgrade to EchoCert, a credential registry the author already had live on Cardano since April 2026.

The demo tells it through two applicants, Chuck and Charles. Chuck has a real diploma; he clicks fields to redact them, and the university learns "the diploma is real, the degree is BSc Computer Science" — nothing more. He proves to three universities in three separate transactions that share nothing linkable. Charles has no diploma, so he forges one; his own device refuses to prove it in ~20 milliseconds, before anything is sent. Three properties, all demonstrated live: selective disclosure, local refusal of forgeries, and measured unlinkability.

The honesty is the interesting part. The Devpost write-up documents a moment where the demo's claim ("three proofs share no identifier") turned out to be false on byte-diff: a 41-byte run was shared, turned out to be the Merkle root, and the claim survived narrower and backed by a repeatable experiment. The anchor is a real Cardano mainnet record minted on 2026-04-11 — the commitment in the demo points at it, and you can check. The author built it pair-programming with Claude Code and disclosed that in the repo.

curated by the VibeFix editors