Add a password to protect your PDF
WhiskFile Protect PDF is a free online tool to add a password to protect your PDF. Files are securely processed on our servers and automatically deleted within one hour.
Enter a password above, then upload your PDF to protect it.
or drag & drop your PDF here
Max 50 MB
Select your file from device or cloud, or drag and drop.
Your file is processed securely. Most files are ready in seconds.
Download the result instantly. Files are auto-deleted after 1 hour.
Secure processing — files encrypted in transit and auto-deleted
Quick Answer
Add a password to protect your PDF. WhiskFile's Protect PDF is free, requires no account, and files are auto-deleted in 1 hour. Files are processed securely on our servers and auto-deleted within 1 hour.
Set a password
Enter an open password (required to view the PDF) and confirm it. The password strength meter helps you choose a strong password with letters, numbers, and symbols.
Configure permissions
Optionally expand Advanced Settings to set an owner password and control permissions. Toggle printing, copying, editing, form filling, and annotations on or off.
Choose encryption level
Select 256-bit AES (recommended, strongest) or 128-bit AES (compatible with older viewers). Both use AES — no weak RC4 encryption.
Upload your PDF
Select or drag and drop your PDF document. The file is encrypted on our server and ready to download in seconds.
Download protected PDF
Download your encrypted, password-protected PDF. Share it knowing only people with the password can open it.
Store your password safely
Save your password in a password manager. There is no recovery if you forget it — the PDF will be permanently locked.
Max file size: 50 MB (free) · 500 MB (paid). Processing time: ~5s on average. Upload one file at a time.
Encrypted transfer
TLS 1.2+ encryption on every connection
Auto-deleted
Files permanently deleted within 1 hour
Private processing
No human access · no AI training · no data sharing
“Password-protecting sensitive documents before sharing gives me peace of mind. Simple and reliable.”
Robert Liu
Compliance Officer
“Redacting confidential info from legal documents is critical. WhiskFile makes it foolproof.”
Nina Patel
Attorney
Help us improve by sharing your experience with Protect PDF.
Faster processing engine
Upgraded processing engine for faster results and improved output quality.
Result preview & sharing
Preview your processed file before downloading, and share results via a secure link.
The open password is required to view the PDF. The owner password controls permissions (printing, copying) without preventing viewing.
256-bit AES encryption by default (the strongest available). 128-bit AES is also available. Both are compatible with all modern PDF viewers.
No. There is no password recovery. Store your password securely — if lost, the PDF cannot be opened without it.
Yes. Set an open password to control who can view the PDF, then use the permissions panel to uncheck 'Allow Printing'. Recipients can view but not print the document.
Yes. Uncheck 'Allow Copying Text' in the permissions panel. This prevents users from selecting and copying text or images from the PDF.
Yes. The permission system is hierarchical. Enable 'Allow Form Filling' while keeping 'Allow Editing' and 'Allow Annotations' disabled. Recipients can fill forms but cannot modify other content.
A strong random owner password is auto-generated for you. This prevents anyone from removing the permission restrictions without the owner password.
256-bit AES is recommended and the default. It provides the strongest encryption available for PDFs. 128-bit AES is faster and compatible with older PDF viewers, but 256-bit is supported by all modern readers.
Yes, briefly. The PDF is encrypted server-side using qpdf for maximum compatibility. Your file is automatically deleted within 1 hour. All transfers use TLS encryption.
No. WhiskFile has no file size limits and no daily task caps for PDF protection. Competitors like iLovePDF (100MB, 2 files) and Sejda (50MB, 3 tasks/hour) impose restrictions.
Yes. WhiskFile password-protects PDFs directly in your browser — no software to install. The encrypted PDF is compatible with Adobe Reader, Chrome, Preview, and all standard PDF viewers.
Currently one PDF at a time. For batch protection, process each file individually — there are no daily limits.
Yes. The encrypted PDF opens in any PDF viewer that supports password-protected files, including the Files app on iPhone, Google Drive on Android, and all major mobile PDF readers.
Yes. Protect PDF on WhiskFile is completely free with no account required. Free users get 7 tasks per day with files up to 50 MB. There are no watermarks on any plan. Pro plans ($4.99/month) unlock unlimited tasks, 500 MB files, batch processing, and API access.
Yes. All file transfers use TLS 1.2+ encryption. Files are processed in isolated containers, scanned for malware with ClamAV, and automatically deleted within 1 hour. WhiskFile does not use your files for AI training or share them with third parties.
Protect PDF accepts PDF files as input and produces PDF output. The maximum file size is 50 MB on the free plan (500 MB for Pro users). There are no page count limits.
See how WhiskFile compares to other PDF tools on features, pricing, and privacy.
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