To use CryptTalk, you will need a device (iPhone, iPad, iPod, etc.) with iOS 8 or newer and about 100 mb of free storage space.
You will also need an internet connection, either by WiFi or mobile data. Everyone participating in a call requires less than 1% IP packet loss and a 80 ms round-trip connection between the parties in the call. For optimal performance, we recommend 0% packet loss and a sub-50 ms round trip time. The CryptTalk app will check that these conditions are met for you.