Two-level controllers hierarchy for a scalable and distributed multicast security protocol Source: Computers & Security, Vol. 24, No. 5, pp. 399-408, August 2005 Authors: Heba K. Aslan Speaker:Pen-Yi Chang

Outline Introduction Related works Proposed scheme Conclusion

Introduction Key distribution Kg, Ki GM GM

Related works(1/2) LKH protocol k1 k1 k2 k3 k3 k4 k5 k6 k7 k7 k8 k9 Broadcast the following: {k1new}k1, {k3new}k3, {k7new}k7, {k1new, k3new, k7new}k15 k1 k1 k2 k3 k3 k4 k5 k6 k7 k7 k8 k9 k10 k11 k12 k13 k14 k15 U1 U2 U3 U4 U5 U6 U7 U8

Related works(2/2) CEKPS protocol kg kg k20 k21 k21 k10 k11 k11 k10 Broadcast kg(new) which encrypted by kg k21(new) = f(kg(new), k21) k11(new) = f(kg(new), k11) k01(new) = f(kg(new), k01) kg kg k20 k21 k21 k10 k11 k11 k10 k11 k11 k00 k01 k01 k00 k01 k01 k00 k01 k01 k00 k01 U1(k1) U2(k2) U3(k3) U4(k4) U5(k5) U6(k6) U7(k7) U8(k8)

Proposed scheme(1/4) Member join k1-16 k1-16 GM k1-8 k1-8 k9-16 k1-4 SM1 SM2 SM3 SM4 k1-2 k1-2 k3-4 k5-6 k7-8 k9-10 k11-12 k13-14 k15-16 k1 k2 k3 k4 k5 k6 k7 k8 k9 k10 k11 k12 k13 k14 k15 k16 U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12 U13 U14 U15 U16 GM generates and broadcasts k1-16(new) which encrypted by k1-16 k1-8(new) = f(k1-16(new), k1-8), k1-4(new) = f(k1-16(new), k1-4), k1-2(new) = f(k1-16(new), k1-2) GM sends {k1-8(new), k1-16(new)}k1 SM1 sends {k1-4(new), k1-2(new)}k1

Proposed scheme(2/4) Member join k1-16 k1-17 k1-8 k9-17 k9-16 k1-4 U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12 U13 U14 U15 U16 GM generates and broadcasts k1-17 which encrypted by k1-16 K9-17 = f(k1-17, k9-16), k13-17 = f(k1-17, k13-16), k15-17 = f(k1-17, k15-16), and k16-17 = f(k1-17, k16) GM sends {k1-17, k9-17}k17 SM4 sends {k13-17, k15-17, k16-17 }k17 k16 k17 U16 U17

Proposed scheme(3/4) k1-16 k1-17 k1-8 k9-16 k9-17 k1-4 k5-8 k9-12 U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12 U13 U14 U15 U16 K1-16 = f(k1-17, k1-8), k9-16 = f(k9-17, k9-12), k13-16 = f(k13-17, k13-14), and k15-16 = f(k15-17, k15) GM sends {k1-16}k9-16, {k9-16}k13-16 SM4 sends {k15-16}k16, {k13-16}k15-16 k16 k17 U16 U17

Proposed scheme(4/4) k1-17 k2-17 k1-8 k2-8 k9-17 k1-4 k2-4 k5-8 k9-12 U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12 U13 U14 U15 k2-17 = f(k1-17, k9-17), k2-8 = f(k1-8, k5-8), k2-4 = f(k1-4, k3-4) GM sends {k2-17}k2-8, {k2-8}k2-4 SM1 sends {k2-4}k2 Then, in order to maintain the balance of the tree, U17 could be moved to replace U1 k16 k17 U16 U17

Conclusion TLCH protocol enhances the group performance in terms of computation.