Certify PDF
Generates a unique RSA-2048 / SHA-256 key pair and embeds a PKCS#7 CMS digital signature into your PDF as an incremental update — verifiable in Adobe Reader, Foxit, and any PDF/A-compliant viewer without altering the original content.
How to use Certify PDF
Upload your PDF
Drag and drop or click to browse. Supports all common formats.
Configure options
Choose settings like output format, quality, or processing mode.
Download result
Your processed file is ready in seconds. Auto-deleted after 1 hour.
Ready to get started?
Free to use. No account required. Files deleted in 1 hour.
Frequently asked questions
Is this PDF tool free?
Yes. Free accounts get 10 operations per day at no cost. No credit card required.
Are my PDFs safe and private?
Your files are encrypted in transit and processed in isolated sandboxes. Files are auto-deleted after 1 hour on the free tier. We never read or share your file contents.
Do you add watermarks to processed PDFs?
Never. All output files are clean — no branding or watermarks added, on any tier. This is a core product promise.
What is the maximum PDF file size?
Free accounts support up to 50 MB. Starter: 150 MB. Pro: 500 MB. Business: 2 GB.