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Sign a PDF with your certificate, and check signatures
A digital signature shows that a document has not changed since it was signed, and names the certificate it was signed with. PDF Stitch signs with the certificate file your certificate authority, Windows or macOS gave you, in the PAdES form that standards-based checkers read, with a box showing your name and the date if you want one. The certificate file and its password stay in your browser. Checking the signatures in a file you open needs no Pro: PDF Stitch shows the name in each signature's certificate, and whether the document is as it was signed.
Checking the signatures in a file you open is free. Signing with your certificate is part of Pro. Pricing
How to do it
- Open your PDF and put the pages together as you want them.
- Open the arrow next to Download and choose Download signed with a certificate.
- Choose your certificate file, type its password, and press Sign and download.
You do not have to take our word for it
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Watch the network
The "Nothing is uploaded" button in the app opens a list of every other site the page has contacted since you opened it, and how often, taken from the browser's own record. Your browser's developer tools show every request, this site's own included.
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Pull the plug
Once the app has loaded, turn off your network and keep working. Text recognition, the document converter and the handwriting fonts work offline too after their first use.
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Redaction that removes
A page with something blacked out is saved as a picture of itself, so the text under the box is gone, and every redacted page is checked before the file is saved.
Questions
- Which certificates can I sign with?
- A .p12 or .pfx file holding your certificate and its private key, with RSA or elliptic curve keys, in the newer form or the older one many files are still in. A certificate on a smart card or USB token cannot be used from a browser.
- Which programs can check the signature?
- Programs that check PAdES signatures, the European standard for signed PDFs, should accept it, though we have not tried them all. Our tests check every signature they make with OpenSSL and Poppler's pdfsig. Whether a program calls the signer trusted depends on whether your certificate comes from an authority it trusts.
- What happens to a signed file I edit?
- The copy you download is a new file, so the old signatures would not hold in it: they are kept on the page as they looked, and are no longer signatures. Sign the new file again if it needs to be.
- Is it free?
- Checking the signatures in a file you open is free. Signing with your certificate is part of Pro.