1. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC A Little Bit About Cookies Instructor: Joseph DiVerdi, Ph.D., M.B.A.

2. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC A Very Simple Transaction

3. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC Simple Transaction w/ Image

4. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC (Infamous) Cookies Introduced by Netscape in Navigator v2.0 Original purpose was to enable a server to track a browser through multiple HTTP requests –Necessary for applications, e.g., shopping cart –Allows storage of a user’s preferences in cookie Intended to improve privacy –Removed the requirement for the server to request and store personal information in a central data bank

5. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC Cookie Issues Rule of unintended consequences Initial implementation allowed any site to request all cookies from a browser thereby revealing (lots of) personal information Quick change to browser to permit delivery of cookies to a particular server (identified by domain) that were issued by that server

6. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC More Cookie Issues Web developers (webmasters?) soon realized that cookies could be “attached” to files other than HTML, e.g., GIF. Combining this capability with the delivery of banner images from advertising companies allowed those advertisers continued access to detailed tracking information Advertisers claim that such tracking permits interested-targeted delivery and reduction of repetitious display There is an opportunity for abuse

7. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC Server-Client Interaction First Step: –Server Sends Set-Cookie Header to Client HTTP/1.0 200 OK Date: Fri 04 Oct 1996 14:31:51 GMT Server: hypothetical.ora.com Set-Cookie: account=04382374 Set-Cookie: userid=woody Content-Type: text/html Content-Length: 1023 Sample Home Page –Client Saves Cookie in Cookie Jar

8. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC Server-Client Interaction Second Step –In a Future Connection Client Recognizes Server's URL Appends Cookie Header GET /index.html Connection: Keep-Alive Host: hypothetical.ora.com Accept: image/gif, image/jpeg, */* Cookie: account=04382374 Cookie: userid=woody

9. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC Cookie Parameters –Name Name given to cookie –Value Value assigned to cookie –Domain Browser only returns cookie to URLs in this domain –Expires Cookie will not be returned after this date –Path Browser only returns cookie to URLs below this path –Secure Browser only return cookie using https protocol

10. A Little Bit About Cookies Fort Collins, CO Copyright © XTR Systems, LLC Cookie File Structure DomainExpirePathSecureExpirationVendor Specific Fields hotwired.lycos.comFALSE/webmonkey/99/09FALSE970380000Lycos_WebographicsSampled www.macfixit.comFALSE/cgi-bin/ultimateFALSE968113043lastLogin2451426.2017 www.macfixit.comFALSE/cgi-bin/ultimateFALSE968113043LastLoginDT09-04-1999%2008%3A17%20PM www.admission.comFALSE/htmlFALSE972187149admissionEN%26US.netscape.comTRUE/FALSE1293840002UIDC199.45.180.157:0912144896:401606.adobe.comTRUE/FALSE1924905604AWID199.45.180.157:10771:912192070:677 www.direct-jobs.comFALSE/FALSE2137622378CFTOKEN11642676 www.direct-jobs.comFALSE/FALSE2137622379CFID122728 www.damark.comFALSE/FALSE2145830703ST_USER0913838850898991.imgis.comTRUE/FALSE1074483659JEB28F799D77DAA0A516CEA8F4B23004E025.zdnet.comTRUE/FALSE1041310803cgversion4.zdnet.comTRUE/FALSE1041310806browserCEA8F4B2383B0D81.yahoo.comTRUE/FALSE1271361603B8vl686iata7fn.ngadcenter.netTRUE/FALSE2145801606NGID2061691f-20905-917899077-5