ISRI Seminar Series / EPP MacArthur Peace and Security Series

The Engineering & Public Policy Department and the PhD Program in
Computation, Organizations & Society present:

Simson Garfinkel, MIT

Thursday, 24 February 2005, 3 pm, NSH 1507

TITLE: "Johnny 2: A user test of key continuity management with S/MIME
and outlook express"

ABSTRACT: After more than 20 years of research,
cryptographically-protected email is still a rarity on the Internet
today. Usability failings are commonly blamed for the current state of
affairs: programs like PGP and GPG must be specially obtained,
installed, and are generally considered hard to ue.  And, while
support for the S/MIME mail encryption standard is widely available,
procedures for obtaining S/MIME certificates are onerous because of
the necessity of verifying one's identify to a Certification
Authority.

Key Continuity Management (KCM) has been proposed as a way around this
conundrum.  Under this model, individuals would create their own,
uncertified S/MIME certificates, use these certificates to sign their
outgoing mail, and attach those certificates to outgoing
messages. Correspondents who wish to send mail that is sealed with
encryption are able to do so because they poses the sender's
certificate.  Mail clients (e.g. Outlook Express, Eudora) alert users
when a correspondent's certificate changed.

We conducted a user test of KCM with 44 email users who had no
previous experience or knowledge of cryptography and email security.
Using a scenario similar to that of Whitten and Tygar's Why Johnny
Can't Encrypt study, we show that while naive subjects generally
understand the gist of digitally signed mail and that a changed key
represents a potential attack, they are less equipped to handle the
circumstance when a new email address is presented simultaneously with
a new digital certificate.

We conclude that KCM is a workable model that can be used today to
improve email security for naive users, but that work is needed to
develop effective interfaces to alert those users to a particular
subset of attacks.


Bio:

Simson L. Garfinkel is a researcher in the field of computer security
and award-winning commentator on information technology.  Currently a
doctorial candidate at MIT's Computer Science and Artificial
Intelligence Laboratory, Garfinkel's research interests include
computer security, the usability of secure systems, and information
policy. He writes monthly columns for Technology Review's Magazine and
website and for CSO Magazine, for which he was awarded the 2004 Jesse
H. Neal National Business Journalism Award for Best Regularly Featured
Department or Column.  Prior to joining CSAIL, Garfinkel founded
Sandstorm Enterprises, a computer security firm that develops
offensive information warfare tools used by businesses and governments
to audit their systems. Garfinkel is the author or co-author of twelve
books on computing, published by O'Reilly and Associates, MIT Press,
Springer-Verlag, and IDG Books. He is perhaps best known for his book
Database Nation: The Death of Privacy in the 21st Century. Garfinkel's
most successful book, Practical UNIX and Internet Security, has sold
more than 125,000 copies since the first edition was published in
1991.