Thank you for supporting us @modernpastor!
We actually discussed app security in our intro post if you are interested to have a detailed read: https://steemit.com/steemit/@yuriks2000/launch-of-new-steemit-mobile-app-today-release-date-is-now

Here is a quick preview:

FAQ: How secure is the app? Can I trust it?

We have set security as the highest priority. Private key will be kept locally on you device's keychain. This private key will never leave you device in it's original form. It will be used for signing posts and will be hashed in a way that it proves that you have it, without actually showing it. We have decided to ask users only for their private posting key, that way you can be sure that your funds are all safe.