Verify a signed document

When a document completes, Korala seals the final PDF with its platform signature and timestamps. The PDF carries everything a validator needs, so anyone who receives the file can check it without a Korala account.

What a completed PDF contains

Part	What it is
Platform signature	A PAdES baseline signature (ETSI EN 319 142-1), made with Korala’s platform certificate, Korala Document Signing Service 2026. It covers the whole document as completed, including the stamped signatures and field values.
Signature timestamp	An RFC 3161 timestamp over the platform signature, from an EU-qualified trust service provider (Sectigo Qualified Time Stamping). It proves the signature existed at that moment.
Validation data	The certificates and revocation data (CRL/OCSP) needed to validate both signature and timestamp, embedded in the PDF’s document security store. The PDF stays verifiable after certificates expire.
Archive timestamp	A second qualified timestamp over everything above: PAdES level B-LTA.

Korala signs and timestamps the Certificate of Completion the same way. The certificate records each signer, the audit trail and the SHA-256 hash of the signed document. See Audit trail and certificates.

Check it in Adobe Acrobat

Open the PDF and choose View → Show/Hide → Side Panels → Signatures. You see two entries:

Signed by Korala Document Signing Service 2026: “Document has not been modified since this signature was applied” and “The signature includes an embedded timestamp”. Acrobat marks the signer’s identity as unknown because Adobe’s trust list does not include Korala’s root certificate. The first line is the integrity result.
Signed by Sectigo Qualified Time Stamping Signer: valid, with its source of trust “obtained from EU Trusted Lists”, and “Signature is LTV enabled”.

If anyone changes the file after completion, Acrobat reports the document as altered or corrupted.

Check it with the EU DSS validator

The European Commission’s DSS demonstration validator checks signatures against the EU Trusted Lists. It rates a completed Korala PDF PAdES-BASELINE-LTA and both timestamps QTSA (qualified). For the platform signature itself it reports the qualification as “not applicable”: Korala, not an EU qualified provider, issued that certificate.

Korala’s certificates

Korala Root CA 2026: download . SHA-256 fingerprint:


fa9bd8c0d32fde45f9b8c526d4275e5ca15f3f39d9a7a5c391dc30201af2a1e9

Korala Document Signing Service 2026, the platform certificate it issues. SHA-256 fingerprint:


3facd9bc00bd4f73bbdc6e3ded8109eadc32eb56409910c992d38212f2a753f1

Tools print the same value with colons and upper case (openssl x509 -noout -fingerprint -sha256 -inform DER -in korala-root-ca-2026.crt). The root’s certificate revocation list is at https://korala.ai/pki/korala-root-ca-2026.crl. If your organization wants Acrobat to recognize Korala as a signer, compare the downloaded root’s fingerprint with the one above, then add it under Acrobat’s trusted certificates.

Older and test documents

Documents completed before 24 September 2026 carry an Adobe-style PKCS#7 signature and an RFC 3161 timestamp from DigiCert, and they remain valid. Acrobat’s Signatures panel and the Certificate of Completion tell you which format a file uses.
Korala signs test (sandbox) documents with a sandbox certificate and no timestamp. They exist for testing, and nothing in them proves when a document was signed.