保护 PDF AES 256 位加密。控制访问 and 权限。
将 PDF 拖到此处
或 点击选择
PDF — Max 100 MB
打开密码
权限（可选限制）
具体结果
典型文件的真实压缩示例
之前 / 之后
未受保护的 PDF
加密的 PDF
AES
256-bit
6s
平均时间
按模式减小
“我的 PDF 合同现在在 5 秒内就有了密码保护！”
How to Password-Protect a PDF Online for Free
Add AES-256 encryption to any PDF in seconds — directly in your browser. Set an open password, permission password or both. Files deleted after 1 hour. No account.
Open password vs permission password
The open password prevents anyone from opening the PDF without the correct key — ideal for confidential documents sent by email. The permission password allows the file to open freely but restricts actions: printing, copying text, editing or adding annotations. You can set one or both passwords simultaneously for layered protection.
AES-256: the gold standard for PDF encryption
FileSwiftly uses AES-256, the same standard used by banking systems, governments and the military. A 256-bit key provides 2^256 possible combinations — even the most powerful supercomputers would take billions of years to crack by brute force. This is the highest encryption level supported by the PDF specification.
Privacy and compliance
Your PDF is transferred over HTTPS TLS 1.3, processed in an isolated environment, and deleted automatically after 1 hour. FileSwiftly never reads or stores document contents. Fully GDPR compliant, no account required.
FAQ
Can I set separate open and permission passwords?
Yes. Set an open password to prevent unauthorized access, and a permission password to restrict printing, copying or editing — independently.
What encryption standard is used?
AES-256 — the industry standard used by banks and governments. The highest encryption level supported by the PDF specification.
Will the protected PDF work on all devices?
Yes. Compatible with Adobe Acrobat, Apple Preview, Google Chrome, Firefox, Foxit and all major PDF readers on Windows, Mac, iOS and Android.
What if I forget the password?
There is no recovery. Store your password in a password manager (Bitwarden, 1Password) before encrypting.
Can I remove the password later?
Yes. Use our Unlock PDF tool — you will need to provide the current open or owner password to remove it.
Does encryption change the visual appearance?
No. The document looks and behaves exactly the same when opened with the correct password. Only unauthorized access is blocked.
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