Sign with a certificate
Add a tamper-evident digital signature, or certify and lock a PDF.
Loading the tool…
About this tool
Sign a PDF with your own digital certificate. Any later change to the document shows up when the signature is checked.
- What certificate do I need?
- A certificate file in .p12 or .pfx format and its password, such as one issued by your organisation or a certificate authority.
- Is it free?
- Yes. Sign Veli’s PDF tools are free to use and need no account.
- Are my files uploaded?
- No. The tool runs entirely in your browser, so your file never reaches Sign Veli’s servers.