Mux can secure your videos with signed URLs that expire after a specified amount of time. These settings control that.
Enable this to secure video URLs. Note that this is not retroactive, meaning any videos encoded with Mux prior to enabling this will not be secured. The same thing goes the other way, turning this off will not remove secure URLs from any videos that were encoded when this was enabled.
Secure Video Expiration
This is the amount of time the user has to start watching the video. The actual expiration time is this value plus the duration of the video.
Secure Thumbnail / GIF Expiration
This is how long a signed URL for a thumbnail image or GIF is valid for. This is not particularly applicable to Media Cloud as any thumbnails will be served from Cloud Storage and not from Mux. But in the case you want to play Mux encoded videos outside of Media Cloud, this setting is included for completeness.
This specifies the amount of time, in hours, that the keys used to sign the URL are rotated.