Before revision:  Then, based on the three-dimensional (3D) interaction characteristics of VR devices, we propose two vrCAPTCHAs design prototypes (i.e., task-driven and bodily motion-based CAPTCHAs).
After revision:  Then, based on the three-dimensional (3D) interaction characteristics of VR devices, we propose two vrCAPTCHA design prototypes (i.e., task-driven and bodily motion-based CAPTCHAs).