As we all know, compared with Word documents, PDF files are more secure,convert word to pdf online free without losing formatting the format will not change because of transmission. So PDF format in some formal occasions is more and more widely used, we also need to give some important PDF documents plus a layer of protection. Today I would like to introduce you to four encryption methods for PDF files.

First, commonly used encryption methods

1, document encryption

Document data encryption technology applies to the entire PDF file system for information encryption, we can choose [File] - [Document Properties] - [Security], and then in the "Security Education" in the "Security Education" select "security and passwords," in the pop-up In the new window,merge 2 jpg files into 1 pdf select "encrypt all the main content of these documents", and check the "need to open the document through the development of a password", enter the user password, click OK.

2, print encryption

use the same method, select File - Document Properties - Security - Password, in the password security settings, change the check box to "Restrictions on the modification and printing of documents,pdf editor free the need for a password to modify the permissions settings", and then enter the password, click "OK", you can restrict other users to print permissions.

3, content encryption

As we all know, the PDF file suffix is ". pdf". We can modify the suffix and change the file extension to encrypt the content.

After the suffix is modified, the file will not be able to open correctly, or open confusion, thus preventing others from viewing the contents of the PDF file.