Since email can be "spoofed", the method you ask about may be needed.
If you don't know a term or terminology, type
What is that?
Would someone explain why or why not a digital signature is necessary?
Help, my PC with Windows 10 won't shut down properly
Since upgrading to Windows 10 my computer won't shut down properly. I use the menu button shutdown and the screen goes blank, but the system does not fully shut down. The only way to get it to shut down is to hold the physical power button down till it shuts down. Any suggestions?