SecureTalk is a secured group message sharing app available for iPhone users. SecureTalk uses your 3G/4G or WiFi (when available) to read & post messages on groups.

It allows you to securely communicate and share messages through groups over HTTPS. Additionally you can impose access control over your groups by password protecting them while creating.
All the messages posted to the groups are retained till 2 hrs, before getting permanently erased. This frees you from the worry of retainability of all your past social activity. You can additionally also choose to include your current location while posting a new message.
All group members are notified about any new message posted on a group via a push notification.
You can choose to leave a group member at any point of time.
The groups presented for joining are capped by a distance parameter which is a 100 mile radius. Groups created beyond 100 miles of your current location are not shown.

You can choose to chat with any member of a group by sending him a buddy request. This provides you an opportunity to securely chat with any member on a one-to-one basis.