File encryption in PHP..?

Question

PHP

The bottom line is, there is an algorithm for reversible encoding of the file, the decrypted file is created as a copy, it is also displayed to the user using header-a content-type, etc., in the next line this file is deleted from the FS.
The question is, it works on a local machine, but will it work on a real server, for example, what about issuing a video file, or downloading a user file, because it can be deleted before it is issued to the user?