Lock PDF Files: 5 Best Services

If your PDF documents contain any sensitive data, you definitely don’t want it to be viewed or copied by any third party. By enabling proper protection, you will avoid such situations. Below are our reviews of the best online and offline services that will let you lock PDF without difficulties.


Using this online service, you can do a full cycle of works with your PDF documents, no matter how complicated they are. The platform offers several easy-to-use pro-grade functional modules and a convenient online editor that lets you create, fill, convert, watermark, and sign forms. There’s no need to download and install PDFLiner, which makes it easier for you to accomplish your tasks.

Locking a PDF with this website can be done easily by uploading the file into your account and enabling encryption. When the operation is done (it takes around 10-20 seconds for average documents), you can save the locked file back to your computer. On the other hand, there’s no need to do it as you can use the sharing features of the platform to deliver locked documents to the needed address or device via integrated email sender or by sharing an access link.

Depending on your tier, you can also share direct access to any uploaded document with up to 5 other users. This makes collaborating on PDF files effortless for remote teams, especially during the lockdown or when you provide outsource services that involve collaborating on PDF documents.

Why choose this service:
  • Straightforward interface;
  • Full-stack online solution for editing, converting, signing, etc.;
  • A quick module for PDF locking;
  • Collaboration with up to 5 users;
  • Compatible with all browsers.


If you are looking for a universal offline solution for working with your PDFs, this one may come in handy. PDFelement lets you make locked PDF documents and adjust permission settings without the need to upload files online. The encryption module lets you select the needed permissions, including printing and editing access rules, password protection, and encryption algorithm. You can choose between such popular standards as 128-bit AES, 256-bit AES, and 128-bit RC4.

Besides, you can use the app to create and edit your docs and convert them into a variety of formats right on your Windows or Mac computer. There’s no collaboration feature, but PDFs can be converted into PowerPoint, Word, and even Excel formats. That’s quite a niche function but may really save your time if you do something like this.

Why choose this service:
  • Can work offline on Mac and Windows;
  • Wide range of formats for conversion;
  • 3 encryption options;
  • Lightweight app.

Vibosoft PDF Locker

There’s no way to edit and share files with the app, but it has the widest range of encryption options and can batch multiple files simultaneously. Actually, you can add as many files as you want to the queue and adjust settings for each file individually. When the PDF is locked, it will be available in the needed folder on your PC or Mac.

The features include setting a password, encryption with 128-bite AES, 40-bit RC4, and 128-bit RC4. By adjusting permissions, you can restrict printing, copying, modifying, adding, document assembling, form-filling, and copying for accessibility. This pro-grade application is quite expensive, but you can try it within one week for free. Actually, it offers good value for money if you need batching multiple large files without the need to upload them.

Why choose this service:
  • Nothing but encryption;
  • The widest range of adjustable permissions;
  • Great for batching multiple documents;
  • Free to try;
  • Works offline.

Nova PDF

Nova PDF is a Windows-only app for managing PDF documents. The service offers pro-grade document adjusting features that let you manage bookmarks, fonts, layouts, signatures, watermarks, and many more features without even opening the documents. The settings can be saved into profiles to let you adjust multiple documents in just a few clicks. You can also merge several documents into one and apply the same adjustments.

Encryption features include 128-bit AES protocol, password protection, and several permission settings, such as printing, copying, and modifying. This app is very helpful for professional users as it saves a lot of time when you need to modify and lock multiple documents. Locking a PDF file is quite simple with this app, so it’s a good solution if you work on Windows and need such a set of offline features.

Why choose this service:
  • Works offline on Windows;
  • Huge discounts apply;
  • Convenient document adjustments without opening the file;
  • Professional-grade interface;
  • Great for batching files.


This web-based solution offers a robust set of free features, including PDF encryption. Unfortunately, the free tier doesn’t let you download the app onto your computer, but you can get an online+desktop tier and manage documents independently from connection availability.

This tool is designed only for doing anything but editing PDF docs. If this is what you want to do, ILovePDF offers pretty simple modules for merging and splitting, locking, encrypting, conversion to Microsoft Office formats, sharing files online, reordering pages, signing, and watermarking documents. Different tiers offer diverse file sizes and file number limits per batch, so choose wisely.

Why choose this service:
  • Lets you work with multiple files, each up to 1GB;
  • Multiple options for modifying documents;
  • Simple web interface;
  • Nice free tier for non-editing purposes;
  • Good for batching files.

Locked & Secure

Locking a PDF with any of these services is effortless. However, you should pick carefully to avoid overpaying for the options you don’t need and vice-versa. Each of the services on our listing has a free trial and different types of tiers/licenses so that you can choose the one that works the best for you. Which service will you choose and why? If you need help, feel free to ask us questions in the comments!
Locking a PDF Online