SSL Traffic Inspection Is the firewall decrypted my session? There is an error "Certificate Not Trusted" (Server Certificate changed to Firewall Cyberoam Certificate). Which public Key I got? Is Main server Public Key or Cyberoam Public Key? Is SSL traffic inspection is same for Authenticated Encryption "GCM" ?
Is the firewall decrypted my session?


In order to inspect the encrypted traffic, your firewall has to decrypt it firts, one way, or the other. Since it can't do it any other way, it "impersonates you/your computer" as the client to the server (and creates an encrypted connection to the server) and also "impersonates the server" to your computer as the client (and creates an encrypted connection with you).


  There is an error "Certificate Not Trusted" (Server Certificate changed to Firewall Cyberoam Certificate).


That's because the firewall has to "impersonate" the server to your client and as it can not use the real servers certificate for authentication/en/decryption/data integrity of the traffic between you (as the client) and it (as the server), it has to use its own. The certificate the firewall uses is issued by its own CA that's obviously not set as trusted in your browser.


  Which public Key I got? Is Main server Public Key or Cyberoam Public Key? 


The firewalls (Cyberoam).


  Is SSL traffic inspection is same for Authenticated Encryption "GCM" ?


AFAIK, yes.

The only problem I see here is if you don't know your encrypted traffic is being inspected / don't want it inspected. If you do, you should set the firewalls CA as trusted in your browser and that'd be that. Here are the instructions from Cyberoam Knowledge Base

Hope I helped.