The document proposes a new security primitive called Captcha as Graphical Passwords (CaRP) that uses hard AI problems from Captcha technology to create a novel graphical password system. CaRP aims to address security issues like online guessing attacks, relay attacks, and shoulder surfing. It can probabilistically thwart automated online guessing even if the password is in the search set. CaRP also aims to solve the "image hotspot" problem in other graphical password systems. The document outlines examples of how CaRP could work and argues that it offers reasonable security and usability for improving online security.