Lock a PDF with a password using strong AES-256 encryption. You can also stop others，來自 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。免帳號即可免費使用：每天 3 項任務（註冊免費帳號可達 6 項），檔案上限 20 MB，且不會加上浮水印。如需更多用量，一日通行證 24 小時 $1.99，Pro 每月 $5.99。
檔案透過 HTTPS 傳輸並存放在您的私人工作區，絕不會被分享或用於訓練 AI。未登入帳號時上傳的檔案會在 24 小時後自動刪除，您也可以隨時自行刪除任何檔案。