Lock PDF

Tags: lock a pdf, how to lock pdf file, lock pdf from printing, lock pdf from editing, lock pdf from copying, pdf print lock

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How to lock PDF file?

PDF is the popular format used to publish and store digital documents. You'd better lock PDF from pringting, editing, copying or even opening to protect your copyright! How to lock a PDF? Password, DRM and third party plug-in are 3 common ways to lock PDF.

But usually users can only use password : open and user password to prevent PDF file from opening and editing. When set user password, you can choose the limitation of file editing by ticking "Allow" or "Not allowed". Well, PDF security level is different with different encryption ways. What's is RC4, AES? How many levels are there to lock PDF documents?

Both RC4 and AES are specifications for the encryption of electronic data. AES, advanced encryption standard, is a higher encryption level than RC4, in other words, PDF files encrypted with AES is more safer than those with RC4 and also more difficult to break. And, more bits, more safer.

Encryption level:
Acrobat 3 and above: 40 bit RC4 40 bit AES
Acrobat 6 and above: 128 bit RC4 and 128 bit AES
Acrobat 9 and above: 256 bit AES
If you lock PDF using 128 bit RC4 in Acrobat6, you can't crack it with password remover supporting 40 bit RC4.

Note: This Version of Lock PDF software is for Windows. If you are using Apple Mac OS, please try Lock PDF Mac.

Cadkas PDF Editor

Cadkas PDF editor is a versatile PDF editing tool which is also a perfect PDF locking program by setting owner and user password in 128 bit encryption. Various restrictions are provided to select for users such as allow to copy, modify, fill in forms, etc. No need for you to worry about the PDF security with advanced encryption engine! In addtion, to decrypt owner password to enable file copying, printing, editing and other restrictions can be wonderfully perfromed by Cadcas. But before opening PDF, you have to type in the open password.

This tool is more than a PDF encryption software to lock PDF but also a powerful PDF editor which enables you to edit text, images, shapes, annotations and any thing of both scanned and normal PDF. With it, you can change PDF security, PDF meta data, bookmarks, text and image property and more you can imgine. If you would like to edit your PDF file before locking it, it's the best choice.

Screenshot of PDF Locker

Alternative Choice: A-PDF password security to lock PDF

This PDF password security is an utility program on windows to help you lock PDF and also remove restrictions of PDF file. Three ways are offered to lock PDF fast and easily. Now let's view features of this software.

Three ways to lock PDF

Singal PDF document security.
Batch PDF document security.
Hot directory: To monitor a diretory by sending PDF files to an output directory after encryption when copied in.

Lock PDF in two methods

Open password to lock PDF: 40 bit RC4 ( Acrobat 3 and above) and higher 128 bit RC4 (Acrobat 5 and above).
Permission Password to lock PDF: Printing, accembly, form field filling in or signning, author coments and form field, changing document, allowing content copying and extraction.

More functions

Change properties like title, author, keywords.
Add expiry date or remove script

Convenient options

Context sensitive menu: Right click on PDF file in Windows Explorer to lock PDF with this tool.
Backup file or remove restrictions option.
Simple interface with clear introductions.
Password pool to try known passwords.

Screenshot of PDF Password Security to lock PDF

PDF Password Security Service

The only difference between A-PDF password security and the service version is that the latter can run as windows service in the background. It will monitor the specified folder and detect the type of PDF file ( encrypted, normal) and perform different functions according to your setting automatically. What you need do is just set options and copy PDF to the monitored file. Say if you have any PDF file you want to: lock PDF from editing, lock PDF from copying and printing, you can try this program.

You should set security level, two passwords, properties, restrictions, and the monitored, output and log file directory file.