First of your need to locate your aspnet_regiis.exe file which is located in one of the directories inside

%systemroot%\Microsoft.Net\Framework\
You can easily navigate to this folder using the WinBtn+R command (Run command) and pasting the above line in the run dialog. The Framework folder contains your installed .NET versions. ##Encrypt section The below command will encrypt the section in the web config file which is located in the C:\Path\To\My\Folder\Contaning\MyWebConfig folder
C:\Windows\Microsoft.NET\Framework\v4.0.30319>aspnet_regiis.exe -pef "connection
Strings" "C:\Path\To\My\Folder\Contaning\MyWebConfig"

Decrypt section

The below command will decrypt the section in the web config file which is located in the C:\Path\To\My\Folder\Contaning\MyWebConfig folder

C:\Windows\Microsoft.NET\Framework\v4.0.30319>aspnet_regiis.exe -pdf "connection
Strings" "C:\Path\To\My\Folder\Contaning\MyWebConfig"

In case of "object not found" error run the command prompt with administrator privileges.