A perfect $(2; 2)$-threshold scheme
You don't need to adress Shamir's, that is just needed for $k&lt;n$. What you do here is along the lines of the proof that OTP is perfectly secure - actually OTP is one example for this (it is not the general case you are given).

Also see Wikipedia the section "trivial secret sharing", which does list elementwise-XOR with a truly random value for the $2,2$ case (also works for $n,n$. There you just choose $n-1$ shares randomly, and calculate the last one).