Ostel is tool funded by the Guardian Project for having end-to-end encrypted phone calls. Their stated goal for Ostel is to promote the use of free, open protocols, standards and software, to power end-to-end secure voice communications on mobile devices, as well as with desktop computers. It is available for Android, iPhone & iPad, Mac, Windows, Linux and Blackberry. Ostel is open source.
Ostel is not free for iPhone & iPad. In fact it It’s a one time paid app for $6.99 you’ll be able to receive encrypted calls. There’s an additional $24.99 one time in-app purchase for the ZRTP extension to be able to make secure calls. To support future developments of Ostel and other open source projects such as this, I didn’t mind paying the cost to have a backup secure call option. Ostel is free for Android.
Once setup, Ostel functions just like the free iPhone & Android Signal app. Both use the ZRTP protocol for end to end encrypted communications.
For Android, Ostel has provided a visual tutorial on how to set it up. Here it is in 14 steps:
- To get started using Ostel with Android, go to Ostel.co and click on Sign me up and complete the process.
- Download the android app CSipSimple.
- Open CSipSimple
- Press the key icon to add an account.
- Add an account.
- Scroll down and click the Open Secure Telephony Network (OSTN) account wizard under Expert.
- You’ll find empty account info.Fill in your newly created Ostel account information.
- You will use the information in the email sent to you.
- To confirm it works, you’ll see OSTN turn green . You are registered!
- To test it, dial 9–1–9–6 to do an echo test.
- In the echo test, you should be able to hear your own voice. Say something. You should hear the words you just said echoed.
- Call someone with Ostel.
- A confirmation code will pop up. Read it to them. If you both have the same code, you’re secure.
- The status should now say “ZRTP – Verified”, showing you that you’re secure.