Apk — Time Graveyard Pin

1234 ^ 0xCA7 = 1234 ^ 3243 = 0x04D2 ^ 0x0CA7 = 0x0875 = 2165 → PIN 002165 Enter 002165 → flag CTF{002165} .

This assumes the context of a CTF (Capture The Flag) or mobile security lab where an Android APK contains a hidden “graveyard pin” mechanism. 1. Challenge Overview Name: APK Time – Graveyard Pin Category: Android Reverse Engineering / Mobile CTF Difficulty: Medium Objective: Find the correct PIN that unlocks the “graveyard vault” inside the app. apk time graveyard pin

current_time = <current HHMM> pin = (current_time ^ 0xCA7) % 1000000 Enter as 6-digit with leading zeros. Example at 12:34: 1234 ^ 0xCA7 = 1234 ^ 3243 =

From XOR: T ^ PIN = 0xCA7 → if T = 0xCA7, PIN=0 → 000000 sum=0. PIN=0 → 000000 sum=0.