This document summarizes a research paper that proposes a Challenge-Response Authentication Protocol (CRAP) to detect Sybil attacks in wireless sensor networks. The CRAP generates unique keys for each transmission to provide encrypted communication. It is used to prevent Sybil attacks where an attacker steals node identities during data transmission. The performance of the detection scheme is evaluated using detection ratio. The proposed CRAP involves three phases: 1) nodes are selected and grouped, 2) two nearby nodes transmit packets to detect collisions indicating Sybil nodes, 3) if no hop is detected between Sybil identities, the nodes are confirmed to be under attack. The scheme is analyzed using performance metrics like packet delivery ratio, energy efficiency, and attack detection ratio.