User blog comment:Manos Stavrakakis/Couldn't anyone (say RECT progress) have hacked the SAO servers?/@comment-1173941-20151221020900

"Maybe", is the answer.

Before getting into the "why", you first have to know that what people often call "hacking", is actually the exploitation of glitches and backdoors in programs. Meaning that the program would need to have some sort of fault in its programing that a "hacker" would have to know about.

Thing is, there are also intentional backdoors that are often built into software. Kayaba being able to lock down SAO, and trap people inside the NerveGear, can be considered a "backdoor".

But hypothetically, Kayaba could create a system that can't be "hacked", in any non-trivial way. You could try to shut down the servers, or break a person's connection manually, but then you would just kill the players.

On the other hand, you could try to "trick" the NerveGear into freeing a player, by performing a "man in the middle attack". This works by intersecting a connection, and sending the client to a different connection. Clearly the NerveGear has a function to "release" a player after its "kill switch" has been activated. The condition to this switch is having the game "Cleared". So with some reverse engineering (assuming the source code is unavailable for various reasons, or if the information about the killswitch is just too well hidden) you could probably determine the API the NerveGear functions under, and how to release a player...

Unless the NerveGear uses an encrypted connection and some high-end verification systems. In which case you'd have to find out the Private Key (a super long password used to encrypt messages sent) that the SAO server uses for every individual player, in order to be able to send a properly encrypted "Release" signal to the NerveGear.

How long could it possibly take to find what the Private Key is? Longer than the lifespan of the universe.

So given proper encryption and verification, no, I don't think RECT could have hacked the SAO servers, especially considering Kayaba was a super genius who probably considered all of what I talked about AND more.