PixelLock

Useful for sending images/text over an open or monitored company/school network. The sender and receiver only need a shared password of their choice and this app to lock/unlock the image/text.

As this is an html file, you can also easily embed this into your own website if desired.

It is also designed to be mobile-friendly, so you can save it on your phone and use it as an app. Should work for any phone.