Community announcement from a small independent app developer (ITAPS LLC; not a student group or local business), in case it's useful to your listeners.

Lock It: Calculator Vault is a free Android privacy app. Looks like a calculator. Opens like a vault. It works as a normal calculator, but when you type your own secret equation and press =, it opens a private vault for photos, notes, passwords and 2FA codes, encrypted with AES-256 on the phone. It also has private messages and calls only with people you invite by key or QR code. Handy for anyone whose phone gets passed around among roommates and friends.

Free to download with ads; optional Premium Pro ($4.99/month) and Offline Vault ($9.99 one time).
Available now on Google Play for Android. iPhone (iOS) version coming soon.
Search "Lock It: Calculator Vault" on Google Play, or: https://play.google.com/store/apps/details?id=com.appfactory.calculator&referrer=utm_source%3Dwuot.org%26utm_medium%3Dlisting%26utm_campaign%3Dfree_ads

Contact: lockit@mail.grokbot.com (ITAPS LLC). Thanks for reading!