A New Two-Server Approach for Authentication with Short Secrets

Burt Kaliski, RSA Laoratories

In typical authentication methods based on short secrets such as passwords, the secrets (or related values) are stored in a central database. Often overlooked is the vulnerability of the secrets to theft en bloc in the event of server compromise. With this in mind, researchers have recently proposed various "password hardening" schemes involving multiple servers, with password privacy assured provided that some servers remain uncompromised.

In this talk, we describe a new, two-server secure roaming system that benefits from an especially lightweight new set of protocols. In contrast to previous ideas, ours can be implemented so as to require essentially no intensive cryptographic computation by clients. This and other design features render the system, in our view, the most practical proposal to date in this area.

Joint work with John Brainard, Ari Juels, and Michael Szydlo.
To be presented at USENIX Security 2003.
Paper available here.

Gates 4B (opposite 490), 05/28/03, 4:30 PM