1. 1 Bounding Virus Proliferation in P2P Networks with a Diverse-Parameter Trust Management Scheme Authors: C. Lin and R. C. Roberto Source: IEEE Communications Letters, Vol. 13, No. 10, pp. 812-814, 2009 Speaker: Shu-Fen Chiou ( 邱淑芬 )

2. 2 Introduction Request file id 3 download

3. 3 Introduction Bounding the virus proliferation. File reputation table Reputation value of the file-- F(i, f l ) Peer trust table Peer trust value (high)--T v (i, j) Infection value (low)--I v (i, j)

4. 4 Proposed method F1234567 F0.50.80.60.40.50.60.7 File reputation table If F(i, f l )>TH R  request file TH R =0.6 F(F, 2)=0.8>0.6 File request

5. 5 Proposed method File search F1234567 F0.50.80.60.40.50.60.7 File reputation table FABCDEF TvTv 0.8 0.70.5 IvIv 0.70.10.6 Peer Trust table If T v (i, j)>TH T  trustee peer, search file TH T =0.5 T v (F, A)=0.8>0.5, T v (F, B)=0.8>0.5 T v (F, C)=no value, ask E, T v (E, C)=0.4 <0.5 T v (F, D)=0.7>0.5 T v (F, E)=0.5=0.5 EABCDEF TvTv 0.70.60.40.7 IvIv 0.10.60.80.6 Peer Trust table

6. 6 Proposed method Post-download update- clean file F1234567 F0.50.80.60.40.50.60.7 File reputation table FABCDEF TvTv 0.8 0.70.5 IvIv 0.70.10.6 Peer Trust table T v (i, j)=αT v (i, j), α>1 α=1.5 T v (F, B)=0.8*1.5=1.2 1.2

7. 7 Proposed method Post-download update- infected file F1234567 F0.50.80.60.40.50.60.7 File reputation table FABCDEF TvTv 0.8 0.70.5 IvIv 0.70.10.6 Peer Trust table T v (i, j)= δ T v (i, j), 0< δ <1 I v (i, j)=I v (i, j)+l F(i, f l )=F(i, f l )+1 δ =0.4 T v (F, B)=0.8*0.4=0.32 I v (F, B)=0.1+1=1.1 F(F, 2)=0.8+1=1.8 0.32 1.1 1.8 IF T v (i, j)<TH W  issue warning message TH w =0.4, T v (F, B)<0.4 Warning message: {ID, v j, f l, △, d} {001, B, 2, 0.5, 5 }

8. 8 Proposed method Post warning update A1234567 F0.70.80.50.40.70.60.8 File reputation table AABCDEF TvTv 0.70.80.30.40.8 IvIv 0.10.20.80.60.1 Peer Trust table 0.35 0.9 1.6 If T v (i, k)>TH T  T v (i, j)=T v (i, j)- △ T v (i,j ) I v (i, j)=I v (i, j)+(d-1)/d F(i, f l )=F(i, f l )+(d-1)/d △ = △ ((d-1)/d) Warning message: {ID, v j, f l, △, d} {001, B, a.mp3, 0.5, 5 } TH T =0.5 T v (A, F)=0.8>0.5 T v (A, B)=0.7-(0.5*0.7)=0.35 I v (A, B)=0.1+4/5=0.9 F(A, 2)=0.8+4/5=1.6 △ =0.5*4/5=0.4 Warning message: { {001, B, 2, 0.4, 5 }

9. 9 Performance analysis 100 nodes, 150 files P d =probability of detect virus P I =probability of infected file FR=File Reputation

10. 10 Performance analysis