That part is really simple: the binary will create a password protected zip. The password is the concatenation of the three flags:* flag{yes_this_is_all_one_big_critical_role_reference}* flag{beep_beeep_bbbeeep_beeeeppppp}* flag{h3av3ns_gate_should_b3_r3nam3d_to_planar_sh1ft_1m0}
The zip file contains a file flag4.txt with the 4th flag:
flag{sorry_no_dragons_hoard_just_internet_points}