How to protect a PDF
- Choose Attach PDF and enter an Open Password of at least six characters, then Confirm Password.
- Keep the permission choices enabled, or set a different Owner Password before restricting printing, copying or editing. New protection uses AES-256.
- Choose Protect PDF, download the copy and test that it opens with the password. Store any owner password securely.
Use a strong, recoverable password
A long unique passphrase is easier to remember and harder to guess than a short password. Send the PDF and its password through different communication channels when practical.
Protection has limits
Password encryption controls access to the file, but it does not prevent an authorized recipient from copying information after opening it. Use secure redaction when sensitive content should not be shared at all.
Separate file access from permission restrictions
The open password controls access to the document. An owner password supplies administrative access when you choose restrictions; keep it somewhere you can retrieve it later. When restricting printing, copying or editing, FlowPDF requires an owner password of at least six characters that differs from the open password. This helps avoid creating restrictions you cannot remove yourself.
A minimum password length is not a measure of strength. Prefer a long, unique passphrase and keep an unprotected original in a secure place. Encryption does not make an authorized reader unable to photograph or reproduce visible information, and some PDF readers do not enforce permission flags. If a recipient should never see certain content, remove it using Redact PDF before protecting the result. Test the protected file before deleting any temporary copy.