Research on interactive CAPTCHA mechanism based on RIA

In order to better ensure the Web security, we designed a CAPTCHA mechanism. It took the RIA areas flexibility combined with interaction design field and used to CAPTCHA design field. This kind of mechanism improves the safety of the CAPTCHA from four aspects. First, we used interactions of man - machines; Second, by comparing the server-side SessionID, random ID and flag variable, it prevents malicious person from bypassing the authentication procedures; Third, it adopt RemoteObject communication mode; Fourth, client's program implemented by Flex. The mechanism well guarant that human can easily through the CAPTCHA test, but computer cannot pass the test.