PDF Shaper
PDF Shaper is a lightweight and simple tool that can split, optimize, merge, watermark, sign, encrypt, decrypt and convert a PDF document. You can also delete or move pages, extract text and images from a document. The program is made for low CPU usage and can operate in batch mode without any lag. It comes in three versions. The free edition offers basic operations for home users, the premium edition expands those features and adds extra tools for advanced users, and the Professional edition comprises all tools, including Optical Image Recognition (OCR) scanner, PDF viewer, and allows commercial use.
Other features are command line support, batch file processing, direct merging for 100 MB+ files, multiple digital signatures, Unicode support, multilingual support, compatibility with the high-DPI resolution, CSV formatting support, and MS Word, DOC & DOCX support. The program is compatible with Windows XP, 7, 8, and 10.
#1 Smallpdf Protect PDF
Smallpdf Protect PDF is an online tool for encrypting a PDF file. The tool will come in handy if you want to secure your document with a password and protect your sensitive document. The tool operates on the cloud, so no need for installation. Just drag and drop your PDF file, enter the password, click encrypt, and download the file to your storage. No maximum file size limit is there.
The file upload is done with a secure SSL connection. No files are kept in its server and are deleted after one hour of uploading. It suggests you a strong password with a suitable character length that is hard to crack. All in all, this easy-to-use tool is a trusted option to encrypt PDF files.