*The laughter of Santa Claus*
XOXOXO it's like XOR XOR XOR.
Let's use CyberChef, and select Xor Bruteforce.
[Solve](https://gchq.github.io/CyberChef/#recipe=XOR_Brute_Force(1,100,0,'Standard',false,true,false,'kks')&input=LSo7OTF%2BLiwxKjE9MTJ%2BOy0qPzwyNy02OzpyfistO349Mjc7MCp%2BKjF%2BPTEwMDs9KnB%2BN3kzfik/Nyo3MDl%2BODEsfissfiw7LjIncH41NS0lPyoqaj01Lj8qLjpqKTAj)
???
PROFIT!
(The flag is: kks{att4ckpatpd4wn})