Grave security issues with the used encryption setup

[patrickfav]

Hi,

You state your code derives it's basic encryption logic from: http://www.java2s.com/Code/Android/Security/AESEncryption.htm (see: https://github.com/kovmarci86/android-secure-preferences/blob/master/secure-preferences/src/main/java/edu/gmu/tec/scout/utilities/Encryption.java)

This example has grave security issues, among others:

• Silently uses the same key if none is provided
• Uses ECB mode wich is utterly insecure if the encrypted data is longer than 16 byte
• Uses broken MD5 hash to derive secret key from password

As I can see you avoid the first point, but still the other points are grave enough to make the whole scheme very unsecure.