To me it wouldn't. Because of Itachi's "By any means...even if you have to kill him?" & "I hope you never have to use it" (along those lines) comments.
Originally Posted by V4yn4rd
If it were just knowledge how to beat the Sharingan/MS or a simple genjutsu counter (for that matter), why would he say that.
Because his comments sound like it's something that can really harm either Naruto (something like repercussions for the power boost....would fit Narutos powerups) or Sasuke, which is more probable.
A way to beat the Sharingan would never make Itachi say such things.
So it's probably some kind of jutsu.
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"