CPSC 426/526 Syil Attks n Dfnss Ennn Zhi Computr Sin Dprtmnt Yl Univrsity
Rll: L-5 Rputtion systms: - Why w n rputtion/trust systms - Wht is glol rputtion mol - Wht is prsonliz rputtion mol - Cs stuis: PgRnk n Crn
Ltur Romp Syil Attks Syil Dfnss Cs Stuy: DSyil Cs Stuy: SyilGur
Tom n Jrry Gms
Tom n Jrry Gms P2P ontnt-shring systms
Tom n Jrry Gms Pollution ttks P2P ontnt-shring systms
Tom n Jrry Gms Pollution ttks P2P ontnt-shring systms Rputtion systms
Tom n Jrry Gms Pollution ttks P2P ontnt-shring systms Rputtion systms Syil ttks
Tom n Jrry Gms Pollution ttks P2P ontnt-shring systms Rputtion systms Syil ttks Syil fnss
Wht is syil ttk? Syil ttk: - Singl vrsry prtns mny fk/syil intitis - Crt hug numr of ounts or intitis - Syil intitis lunh ttks in ritrry wys - Outvoting honst usrs in ny ollortiv systm
Syil
Lt s ttk Crn Crn ssums: - thr is no lrg-sl syil ttk - most of mliious usrs o not ollu - vrsry nnot ontrol th mjority of nos to lunh ttks in smrt wy - Crn tris to hnl syil ttkrs y ig fils, ut this os not work wll Crn is vulnrl to syil ttks
Lt s ttk Crn C: -1 D: +1 Fil1 A: +1 B: +1 C: -1 Fil2 A: -1 B: -1 Fil3 A: -1 C: +1 D: -1 Fil4 A D: -1 Fil5 A: +1 D: -1 Fil6 C: +1 G: -1 Fil7
Lt s ttk Crn C: -1 A: +1 A: -1 A: -1 D: +1 B: +1 B: -1 C: +1 C: -1 D: -1 Fil3 Assum Fil1 5 is pollut n B is syil intity Fil2 Fil4 A D: -1 Fil5 A: +1 D: -1 Fil6 C: +1 G: -1 Fil7
Lt s ttk Crn C: -1 D: +1 Fil1 A: +1 B: +1 C: -1 Fil2 A: -1 B: -1 Fil3 A: -1 C: +1 D: -1 Fil4 A D: -1 Fil5 A: +1 D: -1 Fil6 C: +1 G: -1 Fil7
Lt s ttk Crn C: -1 D: +1 Fil1 A: +1 B: +1 C: -1 Fil2 A: -1 B: -1 Fil3 A: -1 C: +1 D: -1 Fil4 A D: -1 Fil5 A: +1 D: -1 Fil6 C: +1 G: -1 Fil7
Lt s ttk Crn C: -1 D: +1 Fil1 A: +1 B: +1 C: -1 Fil2 A: -1 B: -1 Fil3 A: -1 C: +1 D: -1 Fil4 A B: +1 D: -1 Fil5 A: +1 D: -1 Fil6 C: +1 G: -1 Fil7
# of syil ttkrs utomt syil ttk for $147 # of syil intitis >> # of norml usrs Syil ttkrs n ollu n lunh ritrry ttks
Snrios of Syil Attks Syil ttks xist in ny puli systms/srvis: - Thr is no stringnt rgultory uthority - Attkrs n hv muh mor rsours thn norml usrs - Attkrs n ontrol iffrnt intitis to lunh ttks in ritrry wys,.g., ollusion
Snrios of Syil Attks Snrios r vulnrl to syil ttks: - Rommntion/Rputtion systms,.g., Digg - Gming systms - Soil ntwork systms,.g., Twittr n Fook - Any ollortiv systms
Snrios of Syil Attks Snrios r vulnrl to syil ttks: - Rommntion/Rputtion systms,.g., Digg - Gming systms - Soil ntwork systms,.g., Twittr n Fook - Any ollortiv systms Wht snrios o not hv syil intitis: - This is hr to sy... - It is hr to rt mssiv syil intitis in nk systms - In som snrios, it is not mningful to lunh syil ttks
Ltur Romp Syil Attks Syil Dfnss Cs Stuy: DSyil Cs Stuy: SyilGur
Dfning ginst syil is hllnging Impossil to fn in ntrliz systms unlss spil ssumptions This hs n formlly prov y Douur [IPTPS 02]
Dfning ginst syil is hllnging Dfning ginst syil ttks in ntrliz systms: - Using trust ntrl uthority - Tying intitis to tul humn ings,.g., soil surity numr Not lwys sirl: - Tying intitis to uthority is iffiult in most systms - Snsitiv informtion my sr wy norml usrs - Authority might ottlnk n trgt of ttks
Thnil Solutions Som fnss r propos ginst syil ttks: - Syil ttion: intifying if no is syil intity - Syil tolrn: mking my systm funtions orrtly without intifying syil intitis
Syil tolrn: Thnil Solutions - srviing orrtly without tting syil intitis - lvrging soil ntworks or historil tivitis to upgr th proility of ommuniting with goo usrs - s stuy: DSyil [S&P 09] Syil ttion: - intifying if no is syil intity - lvrging soil ntworks or som osrv hvior pttrns,.g., timing, to tt syil intitis - s stuy: SyilGur [SIGCOMM 06]
Ltur Romp Syil Attks Syil Dfnss Cs Stuy: DSyil Cs Stuy: SyilGur
DSyil [S&P 09] DSyil offrs th following proprtis: - Dsign s on fk n trust - Signifintly migrt th influn of syil intitis - Loss (# of onsum ojt) is provl within O(D logm) vn unr worst-s ttk, whr D is th imnsion of th ojts (lss thn 10) n M is th mx # of syil intitis voting on h ojt - Th gurnt on th loss is optiml.
DSyil [S&P 09] DSyil offrs th following proprtis: - Dsign s on fk n trust - Signifintly migrt th influn of syil intitis - Loss (# of onsum Assumptions? ojt) is provl within O(D logm) vn unr worst-s ttk, whr D is th imnsion of th ojts (lss thn 10) n M is th mx # of syil intitis voting on h ojt - Th gurnt on th loss is optiml.
Assumption: Voting Bhviors Lvrging typil voting hviors of honst usrs - Hvy-til istriution of honst usrs voting hviors - Th xistn of vry tiv usrs who st mny vots % of usrs sting x vots # vots st (on vrious ojs)
Assumption: Voting Bhviors Lvrging typil voting hviors of honst usrs - Hvy-til istriution of honst usrs voting hviors - Th xistn of vry tiv usrs who st mny vots % of usrs sting x vots This ssumption mks sns, us this phnomnon hs n rvl in rl-worl voting systms,.g., Digg # vots st (on vrious ojs)
Th Dsign Insight in DSyil If usr is lry gtting nough hlp, thn o not giv thm mor rputtions This insight nls us to voi giving rputtion to syil intitis tht wnt to otin rputtions frly
Systm Mol Ojts to onsum r ithr goo or Vots r only positiv DSyil is ploy in prsonliz rputtion systms
Systm Mol 2 goo ojts 2 ojts DSyil os not know whih on is goo Eh DSyil roun hs pool of ojts: - DSyil rommns on ojt for Ali to onsum - Ali provis fk ftr onsuming th ojt - DSyil justs rputtion s on th fk
Systm Mol E F H G H 2 goo ojts 2 ojts Eh intity is l to st t most on vot/ojt At most M (.g., 10^10) syil intitis voting on h prout.
Initil Roun: Clssifying Ojts E: 0.2 F: 0.2 H: 0.2 G: 0.2 H: 0.2 Totl: 0.4 Totl: 0.2 Totl: 0.2 Totl: 0.2 Eh intity strts with initil rputtion 0.2 W fin n ojt is ovrwhlming if its rputtion >=1
Th First Roun E: 0.2 F: 0.2 H: 0.2 G: 0.2 H: 0.2 Totl: 0.4 Totl: 0.2 Totl: 0.2 Totl: 0.2
Th First Roun E: 0.2 H: 0.2 H: 0.2 G: 0.2 H: 0.2 Totl: 0.4 Totl: 0.2 Totl: 0.2 Totl: 0.2 Thr is no ovrwhlming ojt
Th First Roun E: 0.2 H: 0.2 H: 0.2 G: 0.2 H: 0.2 Totl: 0.4 Totl: 0.2 Totl: 0.2 Totl: 0.2 Thr is no ovrwhlming ojt 1. Rommn rnom ojt to Ali 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, multiply rputtion of votrs y 2
Th First Roun E: 0.2 H: 0.2 H: 0.2 G: 0.2 H: 0.2 Totl: 0.4 Totl: 0.2 Totl: 0.2 Totl: 0.2 Thr is no ovrwhlming ojt 1. Rommn rnom ojt to Ali 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, multiply rputtion of votrs y 2
Th First Roun E: 0.4 H: 0.4 H: 0.4 G: 0.2 H: 0.4 Totl: 0.8 Totl: 0.4 Totl: 0.2 Totl: 0.4 Thr is no ovrwhlming ojt 1. Rommn rnom ojt to Ali 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, multiply rputtion of votrs y 2
Th Son Roun B: 0.2 F: 0.2 E: 0.4 H: 0.4 H: 0.4 C: 0.2 Totl: 0.4 Totl: 0.8 Totl: 0.6
Th Son Roun B: 0.2 F: 0.2 E: 0.4 H: 0.4 H: 0.4 C: 0.2 Totl: 0.4 Totl: 0.8 Totl: 0.6 Thr is no ovrwhlming ojt 1. Rommn rnom ojt to Ali 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, multiply rputtion of votrs y 2
Th Son Roun B: 0.2 F: 0.2 E: 0.4 H: 0.4 H: 0.4 C: 0.2 Totl: 0.4 Totl: 0.8 Totl: 0.6 Thr is no ovrwhlming ojt 1. Rommn rnom ojt to Ali 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, multiply rputtion of votrs y 2
Th Son Roun B: 0.2 F: 0.2 E: 0.8 H: 0.8 H: 0.8 C: 0.2 Totl: 0.4 Totl: 1.6 Totl: 1 Thr is no ovrwhlming ojt 1. Rommn rnom ojt to Ali 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, multiply rputtion of votrs y 2
Th Thir Roun E: 0.8 H: 0.8 B: 0.2 H: 0.8 G: 0.2 H: 0.8 Totl: 1.6 Totl: 0.4 Totl: 1 Totl: 0.8 Thr r ovrwhlming ojts
Th Thir Roun E: 0.8 H: 0.8 B: 0.2 H: 0.8 G: 0.2 H: 0.8 Totl: 1.6 Totl: 0.4 Totl: 1 Totl: 0.8 Thr r ovrwhlming ojts 1. Rommn Ali rnom ovrwhlming ojt 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, no itionl rputtion givn out (insight #2)
Th Thir Roun E: 0.8 H: 0.8 B: 0.2 H: 0.8 G: 0.2 H: 0.8 Totl: 1.6 Totl: 0.4 Totl: 1 Totl: 0.8 Thr r ovrwhlming ojts 1. Rommn Ali rnom ovrwhlming ojt 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, no itionl rputtion givn out (insight #2)
Th Thir Roun E: 0.8 H: 0.8 B: 0.2 H: 0.8 G: 0.2 H: 0.8 Totl: 1.6 Totl: 0.4 Totl: 1 Totl: 0.8 Thr r ovrwhlming ojts 1. Rommn Ali rnom ovrwhlming ojt 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, no itionl rputtion givn out (insight #2)
Th Thir Roun E: 0.8 H: 0.8 B: 0.2 H: 0.8 G: 0.2 H: 0.8 Totl: 1.6 Totl: 0.4 Totl: 1 Totl: 0.8 Thr r ovrwhlming ojts 1. Rommn Ali rnom ovrwhlming ojt 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, no itionl rputtion givn out (insight #2)
Th Thir Roun E: 0.8 H: 0.4 B: 0.2 H: 0.4 G: 0.1 H: 0.8 Totl: 1.2 Totl: 0.4 Totl: 0.5 Totl: 0.8 Thr r ovrwhlming ojts 1. Rommn Ali rnom ovrwhlming ojt 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, no itionl rputtion givn out (insight #2)
Th Fourth Roun E: 0.8 H: 0.4 B: 0.2 H: 0.4 G: 0.1 H: 0.8 Totl: 1.2 Totl: 0.4 Totl: 0.5 Totl: 0.8 Thr is on ovrwhlming ojt 1. Rommn Ali rnom ovrwhlming ojt 2. Ajust rputtion ftr th fk - if oj is, multiply rputtion of votrs y 0.5 - if oj is goo, no itionl rputtion givn out (insight #2)
Why DSyil works?
Rll: Th First Insight in DSyil Lvrging typil voting hviors of honst usrs - Hvy-til istriution of honst usrs voting hviors - Th xistn of vry tiv usrs who st mny vots % of usrs sting x vots # vots st (on vrious ojs)
Why DSyil works? X A X X X B B C F B C F B C F C F B C F B C F B C F C F B C F Thr is st onsisting of svrl usrs who vot th mjority of goo ojts
Why DSyil works? X A X C X C C X B B C F B C F B C F C F B C F B C F B C F C F B C F Thr is st onsisting of svrl usrs who vot th mjority of goo ojts
Ltur Romp Syil Attks Syil Dfnss Cs Stuy: DSyil Cs Stuy: SyilGur
SyilGur [SIGCOMM 06] SyilGur uss soil ntwork to tt syil intitis: - Rjt proviing srvis to syil intitis - Rly on soil ntwork - Gnrl to ny ntrliz systm snrio Thr is no solution pl of nling you to voi syil ttks ompltly
Soil Ntworks
Lvrging Soil Ntworks Unirt grph Nos = intitis Egs = strong trust -.g., ollgus n frin rltionships
Lvrging Soil Ntworks n honst usrs: On intity/no h Mliious usrs: Multipl intitis h (syil nos) honst nos ttk gs syil nos mliious usr Syil nos my ollu
Lvrging Soil Ntworks n honst usrs: On intity/no h Mliious usrs: Multipl intitis h (syil nos) honst nos ttk gs syil nos mliious usr Syil nos my ollu Ky Insight: It is iffiult for ttkrs to rt xtr gs twn honst nos n syil nos
Ky Insight honst nos syil nos Smll uts Cll ttk g Connting two lrg groups But nnot srh for suh ut whih is NP-hr prolm
Gol of Syil Dfns Gol: Enl vrifir no to i whthr to pt nothr suspt no - Apt: Provi srvi to/riv srvi from - Iliz gurnt: An honst no pts n only pts othr honst nos SyilGur: - Bouns th numr of syil nos pt - Gurnts r with high proility - Approh: Aptn s on rnom rout intrstion twn vrifir n suspt nos
Gol of Syil Dfns Gol: Enl vrifir no to i whthr to pt nothr suspt no - Apt: Provi srvi to/riv srvi from - Iliz gurnt: An honst no pts n only pts othr honst nos SyilGur: - Bouns th numr of syil nos pt - Gurnts r with high proility - Approh: Aptn s on rnom rout intrstion twn vrifir n suspt nos
Gol of Syil Dfns Gol: Enl vrifir no to i whthr to pt nothr suspt no - Apt: Provi srvi to/riv srvi from - Iliz gurnt: An honst no pts n only Not tht rnom rout is iffrnt from rnom wlk!!! pts othr honst nos SyilGur: - Bouns th numr of syil nos pt - Gurnts r with high proility - Approh: Aptn s on rnom rout intrstion twn vrifir n suspt nos
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SyilGur uss Rnom Rout f Rnomiz routing tl: - Rnom 1 to 1 mpping twn inoming n outgoing gs - Routs mrg if rossing th sm g
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Rnom Rout f Bk-trl: - If w know th rout trvrss g, w know th whol rout
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SyilGur Working Prinipl Suspt Vrifir honst nos syil nos Both V n S rnomly hoos nighors to lunh rnom routs Vrifir pts suspt if /2 intrstions twn routs - Rout lngth w - Vrifir s rout stys in honst rgion - Routs from two honst nos intrst
Rnom Rout Intrstion: Norml Suspt Vrifir honst nos syil nos Both V n S rnomly hoos nighors to lunh rnom routs Vrifir pts suspt if /2 intrstions twn routs - Rout lngth w - Vrifir s rout stys in honst rgion - Routs from two honst nos intrst
Rnom Rout Intrstion: Syil SyilGur ouns th numr of pt syil nos within g*w: - g: Numr of ttk gs - w: Lngth of rnom routs Vrifir sm intrstion Suspt Provl gurnts: honst nos syil nos - Convrgn proprty to oun th numr of intrstions within g - Bk-trl proprty to oun th numr of pt syil nos pr intrstion within w
Rnom Rout Intrstion: Syil SyilGur ouns th numr of pt syil nos within g*w: - g: Numr of ttk gs - w: Lngth of rnom routs Vrifir sm intrstion Suspt Provl gurnts: honst nos syil nos - Convrgn proprty to oun th numr of intrstions within g - Bk-trl proprty to oun th numr of pt syil nos pr intrstion within w
Boun # Intrstions Within g Must ross ttk g to intrst vn if syil nos o not follow th protool Vrifir Suspt sm intrstion honst nos syil nos
Boun # Intrstions Within g Must ross ttk g to intrst vn if syil nos o not follow th protool Vrifir sm intrstion Suspt Convrgn: Eh ttk g givs on intrstion t most g honst nos syil nos
Rnom Rout Intrstion: Syil SyilGur ouns th numr of pt syil nos within g*w: - g: Numr of ttk gs - w: Lngth of rnom routs Vrifir sm intrstion Suspt Provl gurnts: - Convrgn proprty to oun th numr of intrstions within g - Bk-trl proprty to oun th numr of pt syil nos pr intrstion within w honst nos syil nos
Boun # Syil Nos Apt within w Suspt Vrifir Bk-trl: - Eh intrstion shoul orrspon to routs from t most w honst nos - Vrifir pts t most w nos pr intrstion honst nos syil nos
SyilGur Summry SyilGur uss soil ntwork to tt syil intitis: - Assumption: Soil ntwork, smll uts, n fst-mixing - Honst no pts <= g*w syil nos - Gnrl to ny ntrliz snrio
SyilGur Summry SyilGur uss soil ntwork to tt syil intitis: - Assumption: Soil ntwork, smll uts, n fst-mixing - Honst no pts <= g*w syil nos - Gnrl to ny ntrliz snrio Cn I mk g=1 n w=1?
Nxt Ltur In th l-7, I will ovr: - Glol srvis om populr - W wnt to ontrol mor - How o Firwll n NAT work? - How to ontrol ntrpris-sl ntwork?