I have a few question about group key in WPA family:
1. How many bits GTK have? How much characters this key have?
2. From which characters GTK can be generated? From 0-9, a-z etc.?
3. Is GTK the final key to encrypt packets (GTK encrypts packets directly?)?
4. If not, what key encrypts multicast traffic? Which formula describes this key derivation from GTK?