A document-open password controls access to the PDF
A PDF document-open password, also called a user password, requires the recipient to enter the password before the file can be opened in a conforming reader.
Adobe distinguishes this from a permissions password, which is used to control or change restrictions such as printing, editing or copying.
1into1 applies 128-bit password protection locally
The Protect PDF tool sends the original browser File to a dedicated local Worker and applies qpdf-based 128-bit protection without first uploading the document to a normal processing server.
The entered password is used as both the user password and owner password in the current implementation.
The page content is preserved rather than rasterized
Protection is an encryption rewrite, not a page-conversion workflow. The tool does not intentionally render every page to JPEG, run OCR or flatten the visible page content as part of password protection.
That makes Protect PDF different from sanitization, grayscale conversion or some compatibility fallbacks that rebuild rendered pages.
Use a strong password and share it separately
A weak password can undermine otherwise valid encryption. Use a password that is difficult to guess and avoid reusing a password already associated with the same recipient or document.
When practical, send the protected file and its password through different communication channels so the password is not bundled with the document itself.
Verify the downloaded copy before sending it
Close the protected file, reopen it in the PDF viewer that matters to your recipient and confirm that the password prompt appears.
Keep the original unprotected file separately. If the source PDF is already encrypted, unlock it first before applying a new password.
Official sources reviewed
- Adobe Acrobat — Encrypt PDFs with passwordsAdobe documents document-open passwords and separate permissions controls for printing, editing and copying.
- Adobe PDF Services — PDF document security and permissionsExplains the distinction between document-open/user passwords and permissions/owner passwords.