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Weird Android Calculator

60 points

321 Solves

Programming

Medium

vidar

Community Rating: 4.52 / 5

I've found this very weird android application.

Seems to be some kind of calculator, but there is something strange with it. Can you find out what it is?

https://mega.nz/#!qXIAgSKZ!u2QBlLV-3G8kmsr6yR0wqpQOFyv89e0WvBt45alBIRY

Flag is in Format: FLAG{...}

Note: You don't really need an android device to solve this. But it might be helpful :)

First 10 Solvers

Rank Username
1 kronos
2 bakkka
3 zipzop
4 krzsernik
5 redcode
Rank Username
6 rhama
7 50530k
8 blakeks4711
9 superior
10 Yeraisci

  • Gj1197

    If you pay close attention to the code it is not that difficult 😊

  • ebouteillon

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    • Szynkie

      I used https://github.com/skylot/jadx It was simpler for me than dex2jar + ...

      • Szynkie

        ohh, i cant edit the comment to make it protected...

        • pizzamonkey00

          Eh, figure most people realize at least one path to the solution uses a decompiler.

    • Caillou

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      • Lriend

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    • Szynkie

      <ol> <li>try it on android</li> <li>open code </li> </ol>

  • Theriphunters

    <ol> <li>Apktool</li> <li>dex2jar</li> <li>jd-gui</li> </ol>

  • glooman

    Any hint, what can I do with the code?

    • glooman

      Solved, but that wasn't easy ;(

  • ghostblade

    https://mega.nz/#!qXIAgSKZ!u2QBlLV-3G8kmsr6yR0wqpQOFyv89e0WvBt45alBIRY

    • glooman

      This is not the correct way to solve this challenge...

  • Karanami

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    • karmanyaahm

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  • Caillou

    I discover something new :) Thanks

  • pizzamonkey00

    Dang, I've been looking through source files for ages but I can't help but feel like I'm looking in all the wrong places. It probably doesn't help I've never programmed for android so I have no idea what things should look like. I'll have to try some more tomorrow.

  • RLangdon

    this was a great challenge. learnt a lot of new tools. Thanks vidar.

  • Londek

    Been overthinking because my logcat didnt work on nox lol

  • impregnable

    Just a tip : Use online apk decompiler to look at the source code