Protect PDF with Password
Add an open-password to a PDF using AES-256 encryption. Strong, standards-compliant and instant.
Quick answer: Add an open-password to a PDF using AES-256 encryption. Strong, standards-compliant and instant.
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Frequently asked questions
- How strong is the encryption?
- AES-256 in CBC mode — the strongest cipher the PDF specification supports, used by every modern PDF reader. With a long, random password, it's effectively impossible to crack offline.
- Can I set permissions like 'no printing'?
- Not in this tool — we only add an open-password, which is the protection that actually matters. Owner-permission flags can be removed by any modern PDF reader and don't provide real security.
- Should I trust an online tool with my PDF?
- We delete the file from server disk and memory within 10 minutes and never log contents. That said, if your PDF is highly sensitive (e.g. a board pack), consider running qpdf locally — the same tool we use server-side.
- What if I forget the password?
- There is no recovery. AES-256 with a strong password cannot be brute-forced in any reasonable time. Save the password in a password manager <em>before</em> you encrypt the file.
- Is the encrypted PDF compatible with phones and old readers?
- Yes — AES-256 PDF encryption is part of the PDF 2.0 spec and works in Adobe Reader, Apple Preview, Foxit, Edge, Chrome and every iOS/Android PDF reader released since 2017.