slides - owasp
slides - owasp
slides - owasp
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A Secure CAPTCHA Implementation<br />
Client 1<br />
GET /captcha.php + *SESSIONID<br />
Server<br />
2 Create a new<br />
**SESSIONID<br />
6<br />
CAPTCHA + **SESSIONID<br />
POST /verify.php + SESSIONID + Solution<br />
5<br />
3<br />
4<br />
7<br />
Create a new<br />
CAPTCHA with<br />
Random Text<br />
Set CAPTCHA<br />
solution in<br />
HTTP Session<br />
Verify the<br />
CAPTCHA<br />
9<br />
8<br />
Clear CAPTCHA<br />
state or HTTP<br />
SESSION<br />
www.foundstone.com<br />
© 2010, McAfee, Inc.