Xctf mobile--app2 problem solving

1. take apk Drag in jadx in

2. Get into SecondActivity.class

doRawData() by native function . Get into ida analysis

3. ida Find doRawData()

  It can be seen that aes encryption , secret key ：thisisatestkey==

4. Decrypt

6. Input found error  , Then static analysis , Find out

  Decryption is

Cas3_0f_A_CAK3