Security

Verify digital signature✓

Check PDF and CMS/P7M/P7S signature cryptography offline, separately from certificate trust.

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Offline signature check

Choose a signed PDF or P7M/CMS file. For a detached P7S signature, also select the original file.

Checks signature cryptography and PDF byte coverage. Certificate trust chains, revocation, qualified-signature status and trusted timestamps are not verified.

How to use Verify digital signature

  1. Choose your files.
  2. Select a signed PDF or attached CMS/P7M file. Detached signatures also require the original file. RSA PKCS#1, RSA-PSS and supported ECDSA signatures can be checked.
  3. Review cryptographic results, PDF byte coverage and certificate dates. Trust chains, revocation, qualified-signature status and trusted timestamps are not validated.

Formats and requirements

Input formats
files
Output
JSON
Availability
Free in your browser and through the CLI
Files per operation
1–2
Browser file limit
128 MiB per file, 128 MiB total

What to expect

Offline cryptographic verification of PDF and CMS/P7M/P7S signatures using embedded certificates. Detached signatures require the original file. Trust chains, revocation, qualified-signature status and trusted timestamps are not checked.

Do my files leave my device?

No. Thanks to advanced file-processing technology, your files are processed directly on your device, inside your browser. OneKit does not receive your input files or results. Required public processing libraries may download when you first use the tool.

File privacy and local processing →

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