Some villains managed to obtain a letter written to Santa. It was addressed to North Pole 34162578 and contained the message:
llHdeoeaanraSt,Iitwyreouthwniiteionttnownyaurothchaitrstsimpasutdaignnerxmbsya{_e_TihLt1_dlueRmM_beyr0}!
We get total of 104 characters = 13 * 8
34162578 is a key
Thinking about this a little bit, the encrypted text is just concatenation of several permutations within 8-character group. Total of 13 groups. See solution.py and the flag is:
xmas{_The_Lit1le_dRumMer_b0y}