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11Kai Hwang, USC, May 2007Kai Hwang, USC, May 2007
Trust Management in Trust Management in P2P and Grid ComputingP2P and Grid Computing
Kai Hwang, Kai Hwang, University of Southern CaliforniaUniversity of Southern California
Presentation Outline:Presentation Outline:
Evolution of Massively Distributed Evolution of Massively Distributed Computing Systems Computing Systems
Trust integration and security binding issuesTrust integration and security binding issues
Security-aware job scheduling in GridsSecurity-aware job scheduling in Grids
P2P Reputation Aggregation SystemsP2P Reputation Aggregation Systems
Further Challenges in Trusted Computing Further Challenges in Trusted Computing
Keynote addressKeynote address at the at the IEEE First Workshop on Trust and Reputation IEEE First Workshop on Trust and Reputation Management in Massively Distributed Computing SystemsManagement in Massively Distributed Computing Systems (TRAM-2007), (TRAM-2007), in conjunction with the in conjunction with the IEEE ICDCS-2007IEEE ICDCS-2007, Toronto, June 29, 2007 , Toronto, June 29, 2007
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 22
Presentation OutlinePresentation Outline: : (Related Publications)(Related Publications)
Trust management and security-aware job scheduling in P2P Trust management and security-aware job scheduling in P2P
and Grid Systems -- and Grid Systems -- ((IEEE Internet ComputingIEEE Internet Computing, Nov. 2005, , Nov. 2005,
IEEE-TC,IEEE-TC, June 2006, June 2006, Journal of Grid ComputingJournal of Grid Computing, Sept. 2005), Sept. 2005)
Reputation systems for structured andReputation systems for structured and
unstructured P2P networks unstructured P2P networks
((IPDPS-2006, IPDPS-2007IPDPS-2006, IPDPS-2007, , IEEE-TPDS IEEE-TPDS April 2007, April 2007,
IEEE-TKDE IEEE-TKDE submitted Jan. 2007) submitted Jan. 2007)
Copyright protection in P2P networks using secure file Copyright protection in P2P networks using secure file
indexing and content poisoning – indexing and content poisoning – ((IEEE-TRAM WorkshopIEEE-TRAM Workshop with with
ICDCS-2007, IEEE-TMM, revised March 2007ICDCS-2007, IEEE-TMM, revised March 2007))
All papers downloadable fromAll papers downloadable from http://GridSec.usc.eduhttp://GridSec.usc.edu
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 33
Evolution from HPC and Clusters to Distributed Evolution from HPC and Clusters to Distributed P2P/Grid Computing and Web ServicesP2P/Grid Computing and Web Services
Mainly for supercompuing
Disparate SystemsResource SharingGeographically SparseWithin a Framework
Distributed Computing
High –Perf. Computing
Disparate Systems
(Sharing)Homogeneous
P2P Clusters
Mainly for file sharing
Geographically Sparse
Resource Sharing
(Close to each other)
Web Services
GRID
Heterogeneous Applications
(Lack of framework)
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 44
P2P Systems, Computational Grids, and P2P Grids
Features P2P Systems Grids P2P Grids
Architecture, Connectivity
Flexible topology,
highly scalable,
autonomous users
Static configuration with limited scalability
P2P flexibility with Grid resource sharing initiatives
Control and Resource Discovery
Distributed control, client-oriented, free in and out, and self-organizing peers
Centralized control, server or supercomputer -oriented with registered participants
Policy-based control, operating with both P2P and Grid resource management
Security, Privacy,
Reliability
Distrusted peers, insecure P2P interactions, and anonymity
Guaranteed trust, more secure with federated users and accountability
Peer-layer reputation system and Grid-layer security infrastructure
Applications and Job
Management
General, content delivery, file sharing, download services
Scientific computing, global problem solving, and hierarchical job management
Support desktop, distributed Grid computing, and community services
Represen-tative
Systems
Gnutella, Chord, CAN, Tapestry, SETI@home, etc.
TeraGrid , GriPhyN Grid, LHC Grid , e-Science, Vaga Grid
Entropia, P2P Grid, PC Grid , Linger Longer
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 55
Some Killer Applications in Some Killer Applications in Grids and P2P NetworksGrids and P2P Networks
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 66
P2
P &
Gri
dA
pp
licati
on
s
Distributed Hash Table (Chord)
New Approaches to Distributed and New Approaches to Distributed and Network-Centric ComputingNetwork-Centric Computing
Multi-Attribute Addressable Network
Distributed Aggregation Tree Distributed
Cardinality Counting
Dis
trib
ute
d I
nd
exin
g
an
d A
gg
reg
ati
on
Tech
niq
ues
Grid Resource Monitoring & Discovery
Distributed RDF
Repository
Collaborative Worm Signature
Generation
P2P ReplicaLocation Service
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 77
The Need of Establishing Cyber Trust The Need of Establishing Cyber Trust
Intrusion
Remote Office
Customer
Supplier
Distributor
Sales rep
Theft of serviceSSSSSSS
Denial of service
Masquerade
Back doors
SabotageSnooping
Disgruntled employees
Viruses
Eavesdropping
Industrial espionage
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 88
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 99
Trust IntegrationTrust Integration over a DHT Overlayover a DHT Overlay
Cooperating gateways working together to establish VPN tunnels for trust integration
Physical backbone
DHT Overlay Ring
Trust Vector
Trust vector propagation
User application and SeGO server negotiation
V
SeGO Server Hosts
VPN Gateway
Site S3
Site S2
Site S1
Site S4
V
V
V
V
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1010
Security Binding in Computing GridsSecurity Binding in Computing Grids Evaluating site trust index using a Evaluating site trust index using a fuzzy-logic based trust modelfuzzy-logic based trust model Fuzzy trust aggregation at the Fuzzy trust aggregation at the intra-site intra-site andand inter-site inter-site levels levels
Matching Job Security demand with
resources conditions
Matching Job Security demand with
resources conditions
Site Trust Index
Defense Capability
SiteReputation
Intersiteaggregation
Intrasiteaggregation
IDS related
Capabilities
Anti-Virus Capabilities
FirewallCapabilities
Secure ExecutionCapabilities
Prior Job Execution
Success Rate
Cumulative Utilization
Job Turnaround
Time
Job Slowdown
Ratio
((IEEE Internet ComputingIEEE Internet Computing, Nov. 2005, , Nov. 2005, IEEE-TC,IEEE-TC, June 2006, June 2006, Journal of Grid ComputingJournal of Grid Computing, Sept. 2005), Sept. 2005)
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1111
Trusted Grid Job SchedulingTrusted Grid Job Scheduling Secure mapping of user jobs onto the Grid sites — the job Secure mapping of user jobs onto the Grid sites — the job security demandsecurity demand (SD) (SD) and and
the site the site trust indextrust index (TI) are attributed to many security measures and trust (TI) are attributed to many security measures and trust parametersparameters
A practical Grid job scheduler should be A practical Grid job scheduler should be risk-resilientrisk-resilient by considering SD and TI by considering SD and TI when mapping jobs to siteswhen mapping jobs to sites
Trust Index of resource sites:Site reputation, prior job success rate, firewalls, intrusion detection, attack history, false alarms, system vulnerability, crypto library, security update frequency, etc.
Security Demand of user jobs:Job sensitivity, peer authentication, encrypted messaging, access control, data integrity, user requirements, job application environment, etc.
User jobs demanding security assurance
Grid resource sites with trust assessed by peers
Job Scheduler
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1212
Two Example Time-Driven Heuristics to Two Example Time-Driven Heuristics to demonstrate the Security Binding Processdemonstrate the Security Binding Process
Min-min heuristics: Min-min heuristics: For each job, the resource site that has the earliest For each job, the resource site that has the earliest
expected completion time is applied first. The job that expected completion time is applied first. The job that
has the minimum earliest expected completion time is has the minimum earliest expected completion time is
executed first to the selected resource site. executed first to the selected resource site.
Sufferage heuristics: Sufferage heuristics: Based on the policy to select a site to a job that would Based on the policy to select a site to a job that would
“suffer” the most in terms of expected completion “suffer” the most in terms of expected completion
time, if that particular site is not assigned yet time, if that particular site is not assigned yet
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1313
Genetic Algorithm (GA)Genetic Algorithm (GA)
Genetic Algorithms (GAs) are based on the concept Genetic Algorithms (GAs) are based on the concept of searching through a large solution space for of searching through a large solution space for acceptable solutions. acceptable solutions.
GA is suitable for job scheduling in heterogeneous GA is suitable for job scheduling in heterogeneous computing and Grid environments. computing and Grid environments. It is powerful for generating good solution. It is powerful for generating good solution.
How a GA works?
0
1
0
1
0
1
1
0
0
1
0
0
0
1
0
0
1
0
0
1
0.3 0.6 0.9 0.6
Initial Population
1
1
0
0
1
0
0
0
1
0
0
1
0
0
1
0.9 0.6 0.9 0.6
After selection
0
0
0
1
0
1
1
0
1
0
0
0
0
1
0
0
1
0
0
1
1.0 0.4 0.9 0.6
After crossover
0
0
0
0
1
1
1
0
1
0
1
0
0
1
0
0
1
0
0
1
1.0 0.4 0.8 0.6
After mutation
0
0
0
0
1
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1414
Genetic Algorithms (GA)Genetic Algorithms (GA) Problem: the initial population is randomly Problem: the initial population is randomly
generated, the whole process takes toogenerated, the whole process takes toolong a time to converge long a time to converge
Evolution times
Solution quality
Random initial population
Good solution is found
Can we start from somewhere here?
How?How How aboutaboutusing using historical historical data ?data ?
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1515
Risk-Resilient Scheduling AlgorithmsRisk-Resilient Scheduling Algorithms
PolicyPolicy Heuristic AlgorithmsHeuristic Algorithms Genetic AlgorithmsGenetic Algorithms
RiskyRisky
Risky-Heuristic:Risky-Heuristic: Jobs are scheduled Jobs are scheduled based on a heuristic algorithm without based on a heuristic algorithm without considering any risk factors. considering any risk factors.
Risky-STGA: Risky-STGA: Jobs are scheduled Jobs are scheduled based on space-time genetic algorithm based on space-time genetic algorithm without considering any risk factors.without considering any risk factors.
PreemptivePreemptive P-Heuristic:P-Heuristic: The job is scheduled to a The job is scheduled to a site that can be preempted due to site that can be preempted due to insecure conditionsinsecure conditions.. Resubmit the failed Resubmit the failed jobs to other available sites.jobs to other available sites.
P-STGA: P-STGA: Job is scheduled based on Job is scheduled based on STGA that allows preemption under STGA that allows preemption under insecure conditionsinsecure conditions.. Resubmit the Resubmit the failed jobs to other available sites. failed jobs to other available sites.
ReplicationReplication R-Heuristic:R-Heuristic: Replicated jobs may be Replicated jobs may be dispatched to multiple sites to prevent dispatched to multiple sites to prevent possible job failures.possible job failures.
R-STGA:R-STGA: STGA that allows replicated STGA that allows replicated jobs to be dispatched to multiple sites jobs to be dispatched to multiple sites to prevent possible job failures.to prevent possible job failures.
Delay-tolerantDelay-tolerant DT-Heuristic:DT-Heuristic: When a failure is When a failure is observed, the scheduler allows job to be observed, the scheduler allows job to be delayed for a preset period of time delayed for a preset period of time before rescheduling the job. before rescheduling the job.
DT-STGA:DT-STGA: STGA that allows job be STGA that allows job be delayed for a preset period of time delayed for a preset period of time before rescheduling the job. before rescheduling the job.
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1616
Performance Metrics Performance Metrics for evaluating the for evaluating the
quality of Trusted P2P/Grid Computingquality of Trusted P2P/Grid Computing
Serious hackers
O
1- Utilization [0, 1.0]
Response Time [0, 4.2105s]
Failure Rate [0, 1.0]
Slowdown Ratio [0, 152]
Makespan [0, 3.3106s]
QoS of P2P/Grid ServicesQoS of P2P/Grid Services
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1717
Performance Results of 7 Job Scheduling Performance Results of 7 Job Scheduling Algorithms over the NAS WorkloadAlgorithms over the NAS Workload
1 2 3 4 5 6 7
0
1x106
2x106
3x106
4x106
5x106
6x106
7x106
ST
GA
Su
ffe
rag
ek-
Ag
gre
ssiv
e
Su
ffe
rag
eC
on
serv
ativ
e
Su
ffe
rag
eA
gg
ress
ive
Min
-min
Ag
gre
ssiv
e
Min
-min
k-A
gg
ress
ive
Min
-min
Co
nse
rva
tive
Ma
kesp
an
(se
con
ds)
1 2 3 4 5 6 7
0.0
2.0x105
4.0x105
6.0x105
8.0x105
1.0x106
1.2x106
1.4x106
ST
GA
Su
ffe
rag
eR
isky
Su
ffe
rag
ef-
Ris
ky
Su
ffe
rag
eS
ecu
re
Min
-min
Ris
ky
Min
-min
f-R
isky
Min
-min
Se
cure
Avg
re
spo
nse
tim
e (
sec)
(a) Makespan(a) Makespan in secondsin seconds (b) Average response time in seconds(b) Average response time in seconds
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1818
Open-Resource Peer-to-Peer NetworksOpen-Resource Peer-to-Peer Networks
In a P2P system, every node acts as both client and server, submitting requests and providing part of the resources
No central coordination or no central database available and no peer has a global view of the entire system.
Overlay Network
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 1919
Cybertrust Demands in Cybertrust Demands in Peer to Peer Computing Peer to Peer Computing
Scalable killer applicationsScalable killer applications on P2P systems on P2P systems
Fast containment of Internet worm outbreaksFast containment of Internet worm outbreaks
Defense against DDoS flooding AttacksDefense against DDoS flooding Attacks
Need Reputation Systems for Need Reputation Systems for P2P networks P2P networks
Copyright protectionCopyright protection in P2P content delivery in P2P content delivery
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2020
P2P Reputation SystemsP2P Reputation Systems Existing ApproachesExisting Approaches
Collecting, aggregating and disseminating feedbacks among Collecting, aggregating and disseminating feedbacks among
peers -- EigenTrust, PeerTrust, PowerTrust, GossipTrust, etc.peers -- EigenTrust, PeerTrust, PowerTrust, GossipTrust, etc.
Common limitations:Common limitations:
Ignore the feedback properties of P2P systems Ignore the feedback properties of P2P systems
Assume an arbitrary feedback distributionAssume an arbitrary feedback distribution
Not in agreement with the reality!Not in agreement with the reality!
Goal: Goal: Scalable, Robust, and Secure Scalable, Robust, and Secure
reputation applications reputation applications
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2121
Transitive Reputation AggregationTransitive Reputation Aggregation
Ask friend’s friends about the reputation of a peer in the system
Ask your friends j
What they think
of node k
And weight each friend’s opinion by
how much you trust him
j
jkij rrrik
'
0
0
0
0
0
0
0
0
0
0
0
0
Node 1
Node 2
Node 4
000000
0
Node 6
j
jkij rrrik
'
While |V(i) – V(i-1)| > δ,
V(i+1) = RTV(i)
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2222
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2323
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2424
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2525
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2626
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2727
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2828
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 2929
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3030
Grid PSA Benchmark ExperimentsGrid PSA Benchmark Experiments
Trusted P2P Grid Computing
Job Makespan in second
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3131
Reputation Systems for Reputation Systems for Unstructured Unstructured P2P NetworksP2P Networks
MotivationMotivation
The Peer-to-Peer (P2P) architectures that are most The Peer-to-Peer (P2P) architectures that are most
prevalent in today’s Internet are decentralized and prevalent in today’s Internet are decentralized and
unstructuredunstructured
Challenges :Challenges :
Short of secure hashing and fast lookup mechanismsShort of secure hashing and fast lookup mechanisms
Most Scalable Reputation System were designed for Most Scalable Reputation System were designed for
structured structured (DHT-based) P2P networks(DHT-based) P2P networks
EigenTrust, PeerTrust, PowerTrust , …….EigenTrust, PeerTrust, PowerTrust , …….
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3232
The GossipTrust SystemThe GossipTrust System Scalable, Robust and Secure reputation system for structured Scalable, Robust and Secure reputation system for structured
P2P networks P2P networks ((IPDPS-2007, IEEE-TKDE submitted 2007IPDPS-2007, IEEE-TKDE submitted 2007))
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3333
Gossip Protocol for Reputation AggregationGossip Protocol for Reputation Aggregation
Make minimal assumptions about the characteristics of Make minimal assumptions about the characteristics of
networks and hostsnetworks and hosts
Tolerate the link and node failuresTolerate the link and node failures
Support the computation of aggregate functions like weighted Support the computation of aggregate functions like weighted
sum, average value and maximum over large collection of sum, average value and maximum over large collection of
distributed numeric values distributed numeric values
One thread sends the halved One thread sends the halved gossip pairgossip pair {½ {½ xxii ( (kk), ½ ), ½ wwii ( (kk)} to )} to
itself (node itself (node ii) and to a randomly selected node in the network. ) and to a randomly selected node in the network.
Another thread receives the halved pairs from other nodes and Another thread receives the halved pairs from other nodes and
computes the updated computes the updated xxii((kk+1) and +1) and wwii((kk+1) +1)
xxii is the is the local scorelocal score and and wwii is the is the consensus factorconsensus factor
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3434
Gossip-based Reputation AggregationGossip-based Reputation Aggregation
d ≤ logb with b =
λ2/ λ1, where λ1 and λ2
are the largest and
second largest
eigenvalues of the
trust matrix S
g = O(log2n)
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3535
Gossip AggregationGossip Aggregation
The updated global score The updated global score
of node of node N2N2 is calculated as is calculated as
vv22((t+1t+1) = ) = vv11(t)×(t)×0.20.2 + + vv22(t)×(t)×0 0
+ + vv33(t)×(t)×0.6 = (1/2)0.6 = (1/2) × ×0.2 + 0.2 +
(1/6)(1/6) × ×0.6 = 0.2 0.6 = 0.2
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3636
Bloom-filter based Reputation StorageBloom-filter based Reputation Storage Bloom filters for reputation retrievalBloom filters for reputation retrieval
Example:Example: a P2P network with 6 nodes, labeled as {0, 1, ..., 5}. a P2P network with 6 nodes, labeled as {0, 1, ..., 5}. v0v0 = 0.05, = 0.05, v1v1 =0.2, =0.2, v2=v2=0.3, 0.3, v3v3 = 0.1, = 0.1, v4v4 =0.3, =0.3, v5=0.05v5=0.05.. Categories 1: {0, 1, 3, 5} and Category 2: {2, 4}Categories 1: {0, 1, 3, 5} and Category 2: {2, 4} mm = 8 bits per filter. = 8 bits per filter. h1h1((xx) = ) = x x ModMod (8) and (8) and h2h2((xx) = ) = xx+2+2
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3737
Bloom filter-based Reputation Storage Bloom filter-based Reputation Storage
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3838
Convergence Rate vs. Gossip ErrorConvergence Rate vs. Gossip Error
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 3939
Aggregation Error vs. Malicious PeersAggregation Error vs. Malicious Peers
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 4040
Further R/D ExtensionsFurther R/D Extensions The architecture of PowerTrust and the GossipTrust can The architecture of PowerTrust and the GossipTrust can
be merged to support both structured and unstructured be merged to support both structured and unstructured P2P networksP2P networks
Prototyping of the PowerTrust, GossipTrust , or a Prototyping of the PowerTrust, GossipTrust , or a combined system. combined system.
Benchmark Evaluation of the prototype systemsBenchmark Evaluation of the prototype systems
Effectiveness of gossip protocol for reputation Effectiveness of gossip protocol for reputation aggregation in P2P networks aggregation in P2P networks
Fast aggregation algorithms, efficient reputation Fast aggregation algorithms, efficient reputation storage with Bloom filters, and secure communication storage with Bloom filters, and secure communication with identity-based cryptography with identity-based cryptography
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 4141
Research Extensions Research Extensions (Continued)(Continued)
Coping with peer abuses and selfishnessCoping with peer abuses and selfishness
Game theoretic and benchmark studies Game theoretic and benchmark studies
Supporting object-based reputationsSupporting object-based reputations
Validating the authenticity of an object (files)Validating the authenticity of an object (files)
Distinguishing between quality-of-service Distinguishing between quality-of-service
and quality of feedbackand quality of feedback
Exploring new killer P2P applicationsExploring new killer P2P applications suchsuch
as copyright protection in P2P content delivery as copyright protection in P2P content delivery
Kai Hwang, IEEE-TRAM Workshop June 29, 2007Kai Hwang, IEEE-TRAM Workshop June 29, 2007 4242
Conclusions:Conclusions: Our security binding technique is applied to improve any Our security binding technique is applied to improve any
time-driven time-driven heuristics for parallel on-line job scheduling heuristics for parallel on-line job scheduling in in an open risky Grid computing environment. an open risky Grid computing environment.
Both NAS and PSA benchmark results show the superiority of Both NAS and PSA benchmark results show the superiority of
STGA over the heuristics algorithms applied. STGA over the heuristics algorithms applied.
It isIt is more resilient to tolerate job delays by calculated risky more resilient to tolerate job delays by calculated risky
conditioning, instead of resorting to job preemption, conditioning, instead of resorting to job preemption,
replication, or assuming unrealistic risk-free operations. replication, or assuming unrealistic risk-free operations.
Peer-based reputation systems are needed for both structured Peer-based reputation systems are needed for both structured
and unstructured P2P networks. Object-based reputation and unstructured P2P networks. Object-based reputation
systems are new challenges systems are new challenges