Conclusion:
Our tour of graphical password research reveals a rich
palette of ideas, but few schemes that deliver on the
original promise of addressing the known problems with
text passwords. Indeed, review of the first era of graphical
password schemes indicates that many of the same
problems continue to re-surface. For graphical passwords
to advance as a serious authentication alternative, we
believe research must be conducted and presented in a
manner allowing systematic examination and comparison
of each scheme’s main characteristics, showing how each
meets the usability and security requirements of specific
target environments.
Authenticating humans to computers remains a notable
weak point in computer security despite decades of effort.
Although the security research community has explored
dozens of proposals for replacing or strengthening
passwords, they appear likely to remain entrenched as the
standard mechanism of human- computer authentication
on the Internet for years to come. Even in the optimistic
scenario of eliminating passwords from most of today's
authentication protocols using trusted hardware devices or
trusted servers to perform federated authentication,
passwords will persist as a means of “last-mile"
authentication between humans and these trusted single
sign-on deputies.
In assessing usability, an apples-to-apples comparison
requires comparing schemes of equivalent security (Figure
10). It is less meaningful to compare the usability of
schemes o ffering vastly diff erent security propositions; if
done, this should be explicitly acknowledged. For
example, in terms of the size of theoretical password
spaces, that of many recognition-based systems is
comparable to 4-digit PINs, while for recall and cuedrecall
systems it is more comparable to text passwords of
8-
characters-or-more. Somewhat longer login times may be
acceptable for password-level systems than for PIN-level
systems, if they provide greater security.