---
url: 'https://www.corbado.com/glossary/kerberos'
title: 'Kerberos'
description: 'Learn how Kerberos enables secure, passwordless authentication with ticket-based access and single sign-on, ensuring seamless & protected network communication.'
lang: 'en'
keywords: 'kerberos'
---

# Kerberos

## What is Kerberos?

Kerberos is a network authentication protocol developed at MIT in the 1980s to enhance
secure communication over untrusted networks. It ensures secure user and service
authentication without transmitting passwords directly, leveraging symmetric key
cryptography and a trusted third party known as the Key Distribution Center (KDC).

## Key Features of Kerberos

> - **Passwordless Authentication:** Employs strong, time-limited secret-key cryptography
>   instead of relying on passwords.
> - **Single Sign-On (SSO):** Users authenticate once to gain access to multiple services
>   without repeated credential entries.
> - **Mutual Authentication:** Verifies the identities of both users and servers, ensuring
>   trusted communication.
> - **Ticket-based System:** Uses encrypted, time-limited tickets containing user identity
>   information for authentication.

---

## How Kerberos Works

1. **Initial Authentication:** The client requests an authentication ticket (TGT) from the
   KDC's Authentication Server (AS).
2. **Ticket Granting:** The KDC validates credentials and returns an encrypted TGT and
   session key.
3. **Service Access:** The client uses the TGT to request a service ticket from the Ticket
   Granting Server (TGS).
4. **Service Authentication:** The service ticket is presented to the server, granting
   access upon verification.

## Advantages of Kerberos

- **Enhanced Security:** Passwords are never transmitted over the network, reducing
  interception risks.
- **Centralized Authentication:** Provides a single point for managing logins and
  enforcing security policies.
- **Scalability:** Designed for large, distributed networks and integration with various
  operating systems.

---

## Applications of Kerberos

Kerberos is widely used in:

- **Microsoft Windows Active Directory**
- **UNIX and Linux systems**
- **Single Sign-On (SSO) implementations**
- **Network service security**, including SSH, POP, and SMTP protocols.