How Cred402 Works
Cred402 verifies a credential against a proof anchored on Hedera — and tells you whether the file changed after it was issued. Verifiers need no account, no login, and no registration: upload a file, settle a tiny pay-per-use fee with x402, and get a tamper-aware report.
Eight steps from upload to proof
Everything is deterministic — no AI guesswork. Each step is observable in the live verification engine.
- 1
Upload a file
Any PDF, PNG, or JPG. No account, no sign-up.
- 2
Hash in memory
The server computes a SHA-256 fingerprint. The file is never stored.
- 3
Identify credential
Match by hash, or by an embedded credential ID for known PDFs.
- 4
402 Payment Required
The full report is gated by a genuine HTTP 402 x402 challenge.
- 5
Settle on Hedera
A small pay-per-use fee settles in testnet HBAR via x402.
- 6
Confirm on Mirror
Settlement is independently verified on the Hedera Mirror Node.
- 7
Run six checks
The deterministic engine resolves each check against the HCS anchor.
- 8
Release the report
A tamper-aware verdict with on-chain proof + HashScan links.
Each check produces PASS / FAIL / WARN / SKIP with concrete evidence.
- 1
Hash integrity
Uploaded SHA-256 vs the HCS-anchored issuance hash.
- 2
Credential known
The credential ID resolves in the registry.
- 3
Issuer registered
The issuer exists and is trusted.
- 4
Revocation
The latest HCS status event is not REVOKED.
- 5
Expiration
The credential is within its valid time window.
- 6
HCS evidence
The issuance event is retrievable from the Mirror Node with a matching hash.
The checks resolve to one verdict by precedence: UNKNOWN → UNREGISTERED_ISSUER → TAMPERED → REVOKED → EXPIRED → VALID.
VALID
Hash matches the anchored original.
TAMPERED
Known credential, but the hash diverges from the anchor.
REVOKED
A CREDENTIAL_REVOKED event exists.
EXPIRED
Outside its valid time window.
UNREGISTERED_ISSUER
Not issued by a registered Cred402 issuer.
UNKNOWN
No matching anchored record was found.
What happens with a custom certificate?
Cred402 verifies a file against a previously registered and anchored proof. It does not guess whether an arbitrary document looks authentic.
Any file can be uploaded
PDF, PNG, or JPG — the app accepts any supported file for verification.
Exact files match by SHA-256
A byte-identical copy of an anchored file resolves against its stored hash.
Known PDFs may match by ID
Some PDFs carry an embedded credential ID the engine can resolve.
Random files → UNKNOWN
A file with no matching anchor and no known ID returns UNKNOWN — not "fake".
PNG / JPEG are hash-only
Images are compared by hash. There is no OCR and no visual/content analysis.
Tampering needs an anchor
To prove a file was altered, its original must have been anchored first (see the demo below).
Verifiers never sign up
Verification is a public, stateless action: you present a file and pay per call. There is nothing to register because Cred402 stores nothing about you — no profile, no email, no wallet connection in the browser. Payment is settled machine-to-machine through x402, so a human or an autonomous agent uses the exact same accountless path.
- No sign-up, no password, no session.
- Pay-per-use — you only pay for the reports you request.
- Identical flow for people and machines.
Every report cites Hedera Consensus Service evidence — an append-only, tamper-evident record you can check yourself on HashScan.
How credentials normally become verifiable
In a real deployment, the institution that issues a credential anchors a proof of it. Cred402 then verifies against that anchor.
Issue
A school or authority issues a credential to a recipient.
Anchor
The issuer submits a minimal proof (a hash + ids, never the file) to a Hedera topic.
Verify
Anyone can later check a file against that anchor — exactly what Cred402 does.
Honest note. This proof of concept uses synthetic issuers and synthetic sample certificates. No real institution, person, or credential is represented. The mechanism is real; the data is fabricated for demonstration on Hedera testnet.
What makes Cred402 different
Not a claim to be the best — a description of the specific design choices.
Comparison is illustrative of design trade-offs, not a ranking of any specific product.
Files are never stored
Uploads are hashed in memory and discarded — only a hash is kept.
No personal data on-chain
HCS records carry a hash, ids, and a timestamp. Never file bytes or PII.
Genuine 402 gate
Reports release only after a real, independently-confirmed x402 settlement.
Replay-safe payments
Each settled transaction unlocks exactly one report (first-use-wins).
Original vs. tampered — Create Tamper Demo
Anchor a file, change one byte of a copy, and watch the verdict flip from VALID to TAMPERED — backed by the same HCS anchor.
- 1Upload original
- 2Anchor proof
- 3Save demo ID
- 4Modify file
- 5Upload modified copy
- 6Tamper result
Disclaimer. Demo registration proves whether a file changed after it was anchored. It does not prove that the uploader is a real school, authorized issuer, or owner of the credential. Records are labelled Synthetic · Demo · Hedera Testnet · Cred402 Demo Issuer.
Choose the file you want to anchor. It is hashed in memory and never stored.
Drop your certificate here
PDF, PNG, JPG supported · max 5 MB
Hashed server-side · files are never stored
- Computes the SHA-256 of your file in memory.
- Creates a synthetic demo credential under the fixed Cred402 Demo Issuer.
- Records a local issuance event (no testnet keys — proof is simulated).
- Returns a demo ID you use to prove tampering next.
No file bytes or personal data are written on-chain — only a hash, ids, and a timestamp.
Who it's for
Employers & registrars
Confirm a certificate hasn't been altered since issuance — no portal account.
Autonomous agents
A machine-readable, pay-per-call 402 API any agent can settle and consume.
Issuers exploring anchoring
See how a hash-anchored credential proves integrity without exposing data.
Developers
A reference implementation of x402 v2 on Hedera with independent settlement proof.
Ready to verify a certificate?
No account needed. Upload a file or try a synthetic sample.