Kerberos, Active Directory’s Secret Decoder Ring

Kerberos Overview

Kerberos is a protocol with roots in MIT named after the three-headed dog, Cerberus. Named because there are 3 parties: the client, the resource server, and a 3rd party (the Key Distribution Center, KDC).

Kerberos can be a difficult authentication protocol to describe, so I will attempt to simplify it as best as possible. Kerberos authentication leverages long-term asymmetric keys (public key) and short-term symmetric keys (session keys).

Asymmetric key cryptography uses two mathematically connected keys where one key is used to encrypt and the other is used to decrypt data. This is most commonly used in Public Key encryption (PKI) where one…