Kerberos is a network authentication protocol designed to provide secure communication over an insecure network. It uses a system of tickets to allow users to prove their identity to services without sending passwords over the network. This helps protect against eavesdropping and replay attacks. The protocol was developed at the Massachusetts Institute of Technology (MIT) in the 1980s and is named after the three-headed dog from Greek mythology. Kerberos relies on a trusted third party, known as the Key Distribution Center (KDC), to issue tickets that grant access to various services within a network.