如何在線上為 PDF 設定密碼保護 — 免費指南
為 PDF 設定密碼保護可以防止未授權的存取，開啟檔案時必須輸入密碼。你也可以獨立於開啟密碼之外，限制列印、複製和編輯權限。這項操作無需 Adobe Acrobat，在線上幾秒鐘即可完成。
兩種 PDF 密碼類型
PDF encryption supports two distinct passwords:
**Open password (user password):** Required to open and view the document. Anyone without this password sees only a password prompt.
**Owner password (permissions password):** Controls what an authorised viewer can do with the document — print it, copy text from it, edit it, or add annotations. The owner password is not required to open the file; it only restricts actions after opening.
You can set either or both. For simple confidentiality (preventing unauthorised viewing), set only an open password.
如何線上為 PDF 設定密碼（逐步說明）
1. Go to the WhiskFile Protect PDF tool.
2. Upload your PDF.
3. Enter an open password in the password field. This is the password recipients will need to open the file.
4. Optionally, configure permissions: allow or restrict printing, copying text, and editing.
5. Click "Protect PDF".
6. Download the encrypted PDF. Test it by opening it in a PDF viewer — you should be prompted for the password.
如何選擇高強度的 PDF 密碼
PDF encryption strength depends on both the encryption level and the password strength. WhiskFile uses AES-256 encryption (the strongest available for PDFs).
Use a password of at least 12 characters with a mix of uppercase, lowercase, numbers, and symbols. Avoid dictionary words, names, or dates.
Important: PDF passwords cannot be recovered if lost. If you forget the password, the only way to access the document is with the original unencrypted version. Always store PDF passwords in a password manager.
如何安全地分享受密碼保護的 PDF
Never send the password in the same message or email as the protected PDF. Instead:
1. Send the protected PDF by email. 2. Share the password via a different channel — text message, phone call, or a separate encrypted message.
This way, if the email is intercepted, the PDF cannot be opened without the separately shared password.
如何從 PDF 中移除密碼
If you know the current password and want to remove it (to create an unprotected version), use the WhiskFile Unlock PDF tool. Enter the existing password, and the tool will produce an unencrypted PDF.
Note: the Unlock PDF tool only works if you know the password. It cannot remove passwords from files where the password is unknown.
常見問題
- WhiskFile 的 PDF 密碼使用哪種加密技術？
- WhiskFile 採用 AES-256 加密技術，這是 PDF 檔案可使用的最高加密級別，與 Adobe Acrobat 使用相同的標準。
- 我可以在沒有 Adobe Acrobat 的情況下為 PDF 設定密碼嗎？
- 可以。WhiskFile 的「保護 PDF」工具可以直接在瀏覽器中為任何 PDF 新增 AES-256 加密，無需安裝 Adobe 軟體。
- PDF 密碼足以保護機密資訊嗎？
- 對於大多數使用情境來說，是的。只要密碼夠強，要用暴力破解法破解 AES-256 加密在計算上是不可能的。密碼若太弱（如短單字、常見片語）則容易被破解。對於極機密的資訊，請使用強密碼並搭配加密儲存等額外安全措施。
- 我可以限制列印但允許檢視嗎？
- 可以。「保護 PDF」工具具備權限控制功能，你可以允許檢視，同時禁止列印、複製或編輯，所有設定皆可獨立調整。