Kerberos

Kerberos is a computer network authentication protocol used to authenticate clients over an unsecured network. It is most commonly used by Windows-based client/server networks. 
It is composed of:
  • authentication service (AS)
  • ticket granting service (TGS)
  • network services (NS)
Kerberos was developed at MIT to protect network services.
The protocol was named after the three-headed guard dog of Hades. 

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