Threema is an opensource, one time payment, secure messaging application based out of Switzerland. Started in 2012, it offers individual, work and education plans. The best thing about Threema, in my opinion, is that it requires no personal information. Linking your e-mail and phone number are optional.
What turns most people off from Threema, is the one time payment. We live in a world where we expect software to be free. However, most of the time, that app you downloaded to your phone from the App Store is paid for in other ways, with your personal data. People will spend $5.00 a day on a cup of overpriced coffee, and another $15.00 for a quick meal at lunch, but will complain about a $5.00 messaging app that will help keep your communications private. If you can look past this, and pay for your privacy, you will be much better off.
Upon downloading the app, either directly from their website here, Google Play Store, or the Apple App Store, you will be prompted to go through the setup process. You may connect an e-mail and/or phone number if you'd like, but it is not necessary. You will be given a Threema ID, which is what you would give to other people to let them connect to you to chat.
Drawbacks of Threema are the requirment to have an Android or iPhone, and lack of multi device support. The multi device support is in the works, so hopefully that will be happening soon.
Below are the steps you will go through to set up your Threema account.
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