Lock a PDF with a password using strong AES-256 encryption. You can also stop others，来自 printing, copying or editing it.
Free · no sign-up · no watermark
Choose the document to protect.
Optionally restrict printing, copying and editing.
Only people with the password can open it.
PDFTEK uses AES-256, the strongest encryption in the PDF standard. Choose a long password: it can't be recovered if you forget it.
Yes, with the Unlock PDF tool, as long as you know the password.
是的。无需账户即可免费使用：每天 3 个任务（注册免费账户可达 6 个），文件最大 20 MB。不添加水印。如需更多，日通行证 24 小时 $1.99，Pro 版 $5.99/月。
文件通过 HTTPS 传输并存储在您的私人工作区，绝不会被共享或用于训练 AI。无账户会话中的文件将在 24 小时后自动删除，您也可以随时自行删除任何文件。