Kerberos: Man’s Best Friend

Introduction and Summary The Authentication Problem Password-Based Authentication Kerberos Comparison Conclusion

The Authentication Problem Users and Services Who are you? What do you want? Why do you keep touching me?

Password-Based Authentication Users and Services Redux Password Files and Hashing One User, One Password, One Service Password Synchronization Methods

Kerberos Why the Silly Name? A Bit of History General Aims and Goals

Building Security: A Real World Example Authentication: The Guards Know You Services: Why You Don’t Show Your Badge at the Water Cooler

Encryption: How to Use Your Password Without Using Your Password Everything is a Number Public-Key vs. Private-Key (Conventional) Passwords = Shared Knowledge

Basics of a Kerberos Transaction Son of Users and Services Everybody Gets a Password Centralized Password Authority A Sample Packet: Example Ticket password{user:client:service:expires:time}

Session Keys and Services Why Do We Need Session Keys? –Replay Attacks –Passwords != Shared Knowledge –Authenticating the Authenticator A Sample Packet: User Authentication session{username:address} + password{session:user:client:service:expires:time}

Ticket-Granting Tickets (And Other Self-Referential Nonsense) Tickets Are a Service Too –Ticket-Granting Servers Grant Tickets –Timestamps Stamp Times –Expiration Expires One User, One Password, Many Services

Realms Kerberos’ Scalability Problems Remote Ticket-Granting Servers Hierarchical Encapsulation

Why You Should Use Kerberos (An Unbiased Review) Unified Password Schemes and Psychology Synchronization Issues Disappear Secure Passwords are Secure Administrators Save Time and Energy

Problems with Kerberos Unified Password Schemes and Psychology Public Terminals and Replay Attacks Supported Applications

General Security Problems (Users Aren’t Too Bright) Bad Passwords are Bad Good Passwords are Bad Security Workarounds for Convenience

Conclusion: Is Kerberos Right for Me? Size Does Matter (A Little) Predicting the Future for Fun and Profit Windows 2000: Engulfed in Evil

Any Questions? Thank you for enduring my presentation. Those of you with questions, please ask them. The rest of you may watch a dancing monkey: