Segmentation of CAPTCHAs Based on Complex Networks

摘要

CAPTCHA is a simple test that is designed to be easily generated by computers and easily recognized by humams, but difficult for computers to solve. It is now almost a standard security technology. The most widely deployed CAPTCHAs are text-based schemes, but to CAPTCHAs, segmenting the connected and distored characters is still an unsolving problem. In this paper, we proposed a Community Divided Model algorithm which based on complex networks to segment these CAPTCHAs. To evaluate the effectiveness of the proposed segmentation algorithm, we conducted several experiments on database which collected some CAPTCHAs from the Internet randomly. The results showed that the proposed algorithm is effective to segment two or more connected and distored characters.