Specifically, everything is designed to make sure the Presense app, its service, and operators can never see any of your contact or personal information. We do this by employing one-way encryption of the data we need to run the service using a salted SHA-1 hashing algorithm, all performed locally on your device.
In non-geek speak, this means our servers store the data we need for the app to operate in a garbled format, which cannot be reversed or read by anyone. Our "secret sauce" allows us to use this garbled data in a way that enables your app to still work.
And – putting aside the fact that we can't read your data – we will never sell or market any information about you.
If you have any questions, please contact firstname.lastname@example.org.
Thanks for using Presense!