kais t a secure group key management scheme for wireless cellular network hwayoung um and edward...
DESCRIPTION
A Secure Group Key Management Scheme for Wireless Cellular Network Introduction : Multicast protocols Growths with multimedia streaming over wireless networks Access control mechanism Session key(SK) “forward message secrecy” and “backward message secrecy” Tree-based key management schemes advantages when update and maintain the SK (computation, communication, storage) Performance issues Scalable no “1 affects n” Matching the key tree to the network topology reduces 33%~45% trafficTRANSCRIPT
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KAIST
A Secure Group Key Management Scheme for Wireless Cellular Network
Hwayoung Um and Edward J. Delp, ITNG’06
2007. 9. 5Kim Pyung
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A Secure Group Key Management Scheme for Wireless Cellular Network
Contents
IntroductionHandoff schemesLocation trackingPre-positioned secret sharingGroup key managementSimulation and resultConclusion
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A Secure Group Key Management Scheme for Wireless Cellular Network
Introduction : Multicast protocols
Growths with multimedia streaming over wireless networksAccess control mechanismSession key(SK)
“forward message secrecy” and “backward message secrecy”
Tree-based key management schemesadvantages when update and maintain the SK(computation, communication, storage)
Performance issuesScalable
no “1 affects n”
Matching the key tree to the network topology reduces 33%~45% traffic
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A Secure Group Key Management Scheme for Wireless Cellular Network
Introduction
The suggested scheme“The neighbors on the key tree are also physical neighbors”A pre-positioned secret sharing scheme
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A Secure Group Key Management Scheme for Wireless Cellular Network
Handoff Schemes
Handoff schemes are based on the location of a userL_ADD : the beginning of handoffL_DROP : the termination of handoff
Soft handoff(30% handoff area)L_ADD : the boundary of overlapping areaL_DROP : the middle of two BSs
Hard handoffThe same with “joining after leaving”
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A Secure Group Key Management Scheme for Wireless Cellular Network
Location Tracking
In Code Division Multiple Access(CDMA)The forward link transmission timing is synchronized within a μs(using self-synchronization, radio beacons, or GPS)The backward link transmission timing is based on the received timing derived from the first multipath component
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A Secure Group Key Management Scheme for Wireless Cellular Network
Pre-Positioned Secret Sharing(PSS)
m-shares
Lagrange interpolation
Over the finite field GF(q)
a0 is the shared secret group key
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A Secure Group Key Management Scheme for Wireless Cellular Network
Pre-Positioned Secret Sharing(PSS)
The pre-positioned sharessharei, 1≤i≤m, i≠j user group
The activation share(AS)sharej key server
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Joining a group{s4-6}k4-5
AS, {s1-6,s4-6}k6
AS, {s1-6}k1-5
A Secure Group Key Management Scheme for Wireless Cellular Network
Group Key Management
M1 M3 M4
B1
G
M6
B2
M2 M5
Group manager
Subgroup managers
Users
s1-5 © AS k1-5
{s1-6}k1-5 s1-6
s1-5 s1-6
s4-5 s4-6
s1-6, s4-6, s6
s4-5 © AS k4-5
{s4-6}k4-5 s4-6
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Leaving a group
AS, {s1-6}k1-5,{s4-6}k4-5
AS, {s1-5}k1-3
A Secure Group Key Management Scheme for Wireless Cellular Network
Group Key Management
M1 M3 M4
B1
G
M6
B2
M2 M5
Group manager
Subgroup managers
Users
s1-3 © AS k1-3
{s1-5}k1-3 s1-5
s1-6 s1-5 s4-6 s4-5
s1-6 s1-5
s4 © AS k4 | s5 © AS k5
{s4-5}k4 s4-5 | {s4-5}k5 s4-5
s4-5 © AS k4-5
{s1-5}k4-5 s1-5
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Handoff
AS, {s5-6}k5,{s5-6}k6AS, {s1-4}k4
AS, {s1-4}k1-3
A Secure Group Key Management Scheme for Wireless Cellular Network
Group Key Management
M1 M3 M6
B1
G
M4
B2
M2 M5
Group manager
Subgroup managers
Users
s1-3 s1-4 s4-6 s5-6
s1-3 © AS k1-3
{s1-4}k1-3 s1-5
s4 © AS k4
{s1-4}k4 s1-4
s5 © AS k5 | s6 © AS k6
{s5-6}k5 s5-6 | {s5-6}k6 s5-6
{s1-6}k1-4, {s1-6}k5-6 ?
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A Secure Group Key Management Scheme for Wireless Cellular Network
Cost Analysis
Tree-based scheme vs Pre-positioned secret sharingd : the degree of the treeh : the height of the tree ( the length of the longest directed path)The group key tree is assumed full and balanced
Comparison of TBC and PSS schemes : Storage cost
TBC PSS
# of keys held by server dn/(d-1) -
# of keys held by each member h -
# of share sets held by server - dn/(d-1)
# of share sets held by each member - h
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Comparison of TBC and PSS schemes : Communication cost
Join Leave
A Secure Group Key Management Scheme for Wireless Cellular Network
Cost Analysis
TBC PSSJoin O(logd(n)) O(d logd(n)) and O(1)
Leave O(logd(n)) O(d logd(n)) and O(1)
Periodic rekeying O(d) O(1)
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A Secure Group Key Management Scheme for Wireless Cellular Network
Cost Analysis
TBC computation cost
PSS computation cost
Server Requesting member
Non-requesting member
Join 2(h-1) h-1 d/(d-1)
Leave d(h-1) 0 d/(d-1)
Periodic rekeying d 1 1
Server Requesting member
Non-requesting member
Join 2(h-1) h-1 d/(d-1)
Leave d(h-1) 0 d/(d-1)
Periodic rekeying 0 0 0
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A Secure Group Key Management Scheme for Wireless Cellular Network
Simulations and Results
Simulation Parameters
Parameter Value
# of MX 1
# of BS 16
# of MS Up to 100 per BS
Call generation Poisson with λ (calls/sec)
Call duration Exponential with 1/μ (1/sec)
User mobility 0-1 km/h (walking)2-5 km/h (running)6-25 km/h (low speed vehicle)25-100 km/h (high speed vehicle)
Cell radius 1 Km
Service Voice, Data, Video
L_ADD 30% of BS coverage area
L_DROP Boundary of BS
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A Secure Group Key Management Scheme for Wireless Cellular Network
Simulations and Results
Number of key transaction 1 x (callgeneration) + 1 x (calltermination) + 2 x (# of Handoff)
No call admission control(CAC) Call admission control(CAC)
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A Secure Group Key Management Scheme for Wireless Cellular Network
Conclusion
New schemethe neighbors on the key tree – physical neighborsPre-positioned secret sharing
Simulation3 - 8 handoff during a call durationNeed of call admission control
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A Secure Group Key Management Scheme for Wireless Cellular Network
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