环境安装见https://bh3mt.cn/archives/linuxhuan-jing-xia-de-android-apkfan-bian-yi-xue-xi-bi-ji

方式1.apktool

# 反编译 APK 
apktool d app.apk -o app_out

再输出文件夹里找到各个字符串（都有等于猜测base64，寻找4倍的字符串）

Z2hUPyEhIX0=

RXYzcnNlXzFz

bW9lY3Rme0Fwa19S

X2Z1Tl9yMQ==

ghT?!!!}

Ev3rse_1s

moectf{Apk_R

_fuN_r1

尝试两种组合

moectf{Apk_REv3rse_1s_fuN_r1ghT?!!!}

moectf{Apk_R_fuN_r1Ev3rse_1sghT?!!!}

发现

moectf{Apk_REv3rse_1s_fuN_r1ghT?!!!}

是正确的