CAPTCHA: Machine or human solvers? a game-theoretical analysis

Zhen Li, Qi Liao

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

2 Scopus citations

Abstract

CAPTCHAs have become an ubiquitous defense used to protect open web resources from being exploited at scale. Traditionally, attackers have developed automatic programs known as CAPTCHA solvers to bypass the mechanism. With the presence of cheap labor in developing countries, hackers now have options to use human solvers. In this research, we develop a game theoretical framework to model the interactions between the defender and the attacker regarding the design and countermeasure of CAPTCHA system. With the result of equilibrium analysis, both parties can determine the optimal allocation of software-based or human-based CAPTCHA solvers. Counterintuitively, instead of the traditional wisdom of making CAPTCHA harder and harder, it may be of best interest of the defender to make CAPTCHA easier. We further suggest a welfare-improving CAPTCHA business model by involving decentralized cryptocurrency computation.

Original languageEnglish
Title of host publicationProceedings - 5th IEEE International Conference on Cyber Security and Cloud Computing and 4th IEEE International Conference on Edge Computing and Scalable Cloud, CSCloud/EdgeCom 2018
EditorsMeikang Qiu
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages18-23
Number of pages6
ISBN (Print)9781538658505
DOIs
StatePublished - Jul 27 2018
Event5th IEEE International Conference on Cyber Security and Cloud Computing and 4th IEEE International Conference on Edge Computing and Scalable Cloud, CSCloud/EdgeCom 2018 - Shanghai, China
Duration: Jun 22 2018Jun 24 2018

Publication series

NameProceedings - 5th IEEE International Conference on Cyber Security and Cloud Computing and 4th IEEE International Conference on Edge Computing and Scalable Cloud, CSCloud/EdgeCom 2018

Conference

Conference5th IEEE International Conference on Cyber Security and Cloud Computing and 4th IEEE International Conference on Edge Computing and Scalable Cloud, CSCloud/EdgeCom 2018
Country/TerritoryChina
CityShanghai
Period06/22/1806/24/18

Keywords

  • Bitcoins
  • Blockchain
  • CAPTCHA
  • Computer Security
  • Cryptocurrency
  • Economics
  • Game Theory
  • Human Solver
  • Machine Solver

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