BaseActivity:
A clear back stack method.
Shared preferences only for activity and encrypted or not.
BaseFragment:
Back event listener with the same functionality as onBackPressed than activity class.
Shared preferences only for fragment, and encrypted or not.
SecurePreferences:
Key-value encrypted shared preferences.
AESCipher:
Encrypt/Decrypt strings with AES 128-bits using key based on device ANDROID_ID.