[abritishguy]

Display which cipher is being used?

2G is insecure regardless of whether encryption has been turned off or not, it can be decrypted on the fly with very modest hardware so the indicator telling you what connection you have is as good as telling you whether it is "secure" or not.

> Detect hidden SMS

Not really feasible - there are tons of different types of "hidden" sms that are routinely used by the network but can be spoofed by a third party.

> Detect SIM card app installations through public APIs

This won't work unless it is rooted and this messages have to be signed from the network anyway.