While installing UE4 there are multiple admin prompts. I make it a habit of checking all the certificates. Once I got to the certificate I noticed that its end date was the 1st of last month. I wasn’t prompted with an error, so I’m guessing there is the possibility that it is somehow still valid. However from what I’ve seen there is no place on your site with information to validate downloads through either their checksum or certificate information. It would be great if there was a more robust section on security information and validation.