How to verify a certificate of destruction

Every tScrub certificate carries a QR code in the corner. Scanning it with an ordinary phone camera opens tscrub.com/verify-offline with a signed code for that certificate already filled in. The signature is checked on the phone, against the key published at /.well-known/tscrub-cert-key.json, so the check works with no network at all. The same certificate ID also has a public record at tscrub.com/verify?cert=…, which needs a connection and shows the fuller picture. Between them, a static PDF becomes something a client, an auditor or a regulator can check without calling you.

Certificates issued before 21 October 2026 carry the record link in the QR instead of a signed code. They verify exactly as they always did — they just need a connection to do it.

Which QR code is on your certificate?

The caption printed under the code tells you, without scanning anything:

• "Verify offline or online" — the code is a signed message: a format version, the key ID tscrub-vendor-1, the Certificate ID, the issue timestamp, and a signature over those three. About 189 characters, which is why it is printed slightly larger than a plain link needs to be: a cheap phone camera has to decode it reliably.
• "Verify online" — the code is the record link, tscrub.com/verify?cert=…. This is every certificate issued before 21 October 2026, plus any certificate generated while the vendor signing key was unavailable. Nothing is wrong with either case.

What the code never contains: your name, the drive serials or models, the PDF hash, or an email address. A QR on a printed certificate is public forever and gets photographed by strangers, so it carries the minimum needed to prove issuance and nothing that identifies you or your assets. The Certificate ID inside it is what then unlocks the online record, so one scan is enough for both checks.

What the QR check proves — and what it does not

The signed code attests that tScrub issued that certificate ID at that time and that the code has not been altered since. It is the one check that needs no signal, no account and no database, which is what an auditor with a segregated laptop, or a phone in aeroplane mode, actually needs.

It cannot confirm what the certificate records about the drives: a page on a phone holds no database. For that, open the online record for the same certificate ID, or scan the QR with a normal camera app while online. An auditor who wants both can enter the Certificate ID printed on the paper into the verifier: a code lifted from a different certificate is then rejected.

What the verification page checks

• The certificate ID exists in tScrub's issuance records.
• The document hash matches the certificate that was actually issued.
• The certificate's tier — and therefore what the signature means.

A match returns "Certificate Verified." A certificate that isn't found, or that has been altered, won't verify — which is exactly the point.

Machine-readable certificate (JSON-LD)

Every certificate also ships as a signed JSON-LD document — the same link with &format=jsonld. It's the certificate as structured data: certificate and chain-of-custody IDs, every drive and report, the PDF's SHA-256, and a detached Ed25519 signature over the whole document.

• Verifiable offline — the public key is published at /.well-known/tscrub-cert-key.json, so any script can check the signature without calling tScrub. The certificate QR uses the same key, so a phone can check it too.
• Third-party timestamped — the signature carries an RFC 3161 timestamp from a timestamping authority, anchoring when it was issued.
• Built for automation — compliance platforms, procurement bots and LLM auditors can ingest the certificate directly, no PDF parsing.

Free vs paid certificates at verification

Verification is honest about what it can confirm:

• Vendor-signed (paid) — the page fully confirms the certificate and its attribution.
• Self-signed (free) — the page explains that the certificate is self-signed and cannot be independently attributed, with a prompt to upgrade. It's tamper-evident but not independently confirmable.

Why independent verification matters

A certificate you issue is a claim you make. A certificate a third party can verify is evidence they can rely on. That's the difference between a PDF that reassures internally and a record that survives external scrutiny — especially for drives that left your control.

FAQ

Does the QR code work without an account?

Yes. The verifier and the record page are both public — no login required. That's what makes them useful for third parties.

Does it work without a network connection?

Yes, for the signed code. Load tscrub.com/verify-offline once and it keeps working offline; after that a scan shows the verdict on the device. The record page and the JSON-LD document still need a connection.

What if a certificate doesn't verify?

That means the document or the record doesn't match. It's a sign to check the file's authenticity — and the source you received it from.