Observation points
- As in ecryption we see 9 key length
- part of key is SHELL
Let's guess one more char and make key length 7 by adding { so current key becomes SHELL{
In Output we get (using solution.py)
We got a meaning full string "XORISC" still need more three characters to complete key .... Might it be "XORISCOOL" which actually becomes key
And we get the flag :- SHELL{X0R_1S_R3VeR51BL3}