Privacy Protection Password

My phone is asking for a privacy protection password but i totally don't know what to do. i heard of flashing it but i dont have its firmware and its exact software in general. details

kernel version
3.4.5-526212
sei@sei//44111
wed arpril 24/20 59:59 KST 2015

android version: 5.1.2

model number z3
build number: 23. 0.1 A77
links will be fine wiyh me