If - big IF - the game designer has not relied on his encoded .plr files to be unbreakable (yes, designers tend to overestimate their skills
) he could have easily made cheating impossible. Let players only submit orders, execute everything on host while error-checking as the SE programm checks where you only can enter valid orders. Hacking the strength of DUCs - impossible, should be stored in the host data file and accessed new for every combat for every ship. Hacking the number of components on a ship design - detectable if the designs are also stored in host data and applied fresh every turn, and error-checked when created. Hacking ship positions - futile if only move orders are transmitted and not final ship positions (move fleet X to system Y sector Z - ok, will take 500 gazillion turns but I'll start moving them...
)
So, if proper design decidions have been made, cheating vie turn submision should be next to impossible. Of course, if the SE programm already executes the orders and then only sends the results, not the orders, to the host, hacking is possible and how easy it is only depends on the quality of the encryption of the .plr file. But the pricipal flaw of this kind of design is known for years. On the other hand, SE is very old...
Another thing is the .gam and log files that all players get. As all players get the same file and the info contained is only filtered by the SE programm, there is a lot of info in the results that should not be seen by a player. Only individual result files for each player would make this 100% safe, but also complicate the hosting process. All that remains here between cheating hackers and their success is the quality of the encryption. I hope it is good. But as the decrypting programm (SE) is available, hacking is possible and I am sure a lot of people - including myself - would theoretically be able to do it. It is not easy and will cost a lot of time - and I just don't consider it worth my time. Let's hope we don't get too many kiddies with too much time at their hands as players...