Cryptanalysis of the convex hull click human identification protocol

Hassan Jameel Asghar, Shujun Li, Josef Pieprzyk, Huaxiong Wang

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review


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. In this paper we show two efficient probabilistic attacks on this protocol which reveal the user's secret after the observation of only a handful of authentication sessions. 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 which cross the threshold of usability.

Original languageEnglish
Title of host publicationInformation Security - 13th International Conference, ISC 2010, Revised Selected Papers
EditorsMike Burmester, Gene Tsudik, Spyros S. Magliveras
Place of PublicationBerlin
PublisherSpringer, Springer Nature
Number of pages7
ISBN (Print)9783642181771
Publication statusPublished - 2010
Event13th Information Security Conference, ISC 2010 - Boca Raton, FL, United States
Duration: 25 Oct 201028 Oct 2010

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume6531 LNCS
ISSN (Print)03029743
ISSN (Electronic)16113349


Other13th Information Security Conference, ISC 2010
Country/TerritoryUnited States
CityBoca Raton, FL


Dive into the research topics of 'Cryptanalysis of the convex hull click human identification protocol'. Together they form a unique fingerprint.

Cite this