A three-way investigation of a game-CAPTCHA: automated attacks, relay attacks and usability.
Manar MohamedNiharika SachdevaMichael GeorgescuSong GaoNitesh SaxenaChengcui ZhangPonnurangam KumaraguruPaul C. van OorschotWei-bang ChenPublished in: AsiaCCS (2014)