TY - JOUR
T1 - Cryptanalysis of the convex hull click human identification protocol
AU - Asghar, Hassan Jameel
AU - Pieprzyk, Josef
AU - Li, Shujun
AU - Wang, Huaxiong
PY - 2013
Y1 - 2013
N2 - Recently, a convex hull-based human identification protocol was proposed by Sobrado and Birget, whose steps can be performed by humans without additional aid. The main part of the protocol involves the user mentally forming a convex hull of secret icons in a set of graphical icons and then clicking randomly within this convex hull. While some rudimentary security issues of this protocol have been discussed, a comprehensive security analysis has been lacking. In this paper, we analyze the security of this convex hull-based protocol. In particular, we show two probabilistic attacks that reveal the user's secret after the observation of only a handful of authentication sessions. These attacks can be efficiently implemented as their time and space complexities are considerably less than brute force attack. We show that while the first attack can be mitigated through appropriately chosen values of system parameters, the second attack succeeds with a non-negligible probability even with large system parameter values that cross the threshold of usability.
AB - Recently, a convex hull-based human identification protocol was proposed by Sobrado and Birget, whose steps can be performed by humans without additional aid. The main part of the protocol involves the user mentally forming a convex hull of secret icons in a set of graphical icons and then clicking randomly within this convex hull. While some rudimentary security issues of this protocol have been discussed, a comprehensive security analysis has been lacking. In this paper, we analyze the security of this convex hull-based protocol. In particular, we show two probabilistic attacks that reveal the user's secret after the observation of only a handful of authentication sessions. These attacks can be efficiently implemented as their time and space complexities are considerably less than brute force attack. We show that while the first attack can be mitigated through appropriately chosen values of system parameters, the second attack succeeds with a non-negligible probability even with large system parameter values that cross the threshold of usability.
UR - http://www.scopus.com/inward/record.url?scp=84874795797&partnerID=8YFLogxK
U2 - 10.1007/s10207-012-0161-x
DO - 10.1007/s10207-012-0161-x
M3 - Article
AN - SCOPUS:84874795797
SN - 1615-5262
VL - 12
SP - 83
EP - 96
JO - International Journal of Information Security
JF - International Journal of Information Security
IS - 2
ER -