sat: situation aware trust architecture for vehicular networks xiaoyan hong, univ of alabama dijiang...
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SAT: Situation Aware SAT: Situation Aware Trust Architecture for Trust Architecture for Vehicular NetworksVehicular Networks
Xiaoyan Hong, Univ of Alabama
Dijiang Huang, Arizona State Univ
Mario Gerla, UCLA
Zhen Cao, UCLA
Vehicular Networking AppsVehicular Networking Apps Safe navigation:
◦ Forward collision warning ◦ Advisories to other vehicles: ice on
bridge, congestion ahead, etc
Potholes
Forward Collision Warning
Non safety applications◦ Traffic monitoring (with
navigator)◦ Pollution probing◦ Pavement conditions (e.g.,
potholes)◦ Content distribution◦ Urban surveillance
Primary security goals: ◦ Message integrity and
authentication
◦ Detect misuse by naïve or malicious drivers.
◦ Guarantee message sender
privacy
Existing Trust in Vehicle NetsExisting Trust in Vehicle Nets
Hey buddy, traffic ahead
Entity Trust
Are you serious?-origin integrity-data integrity
Hey buddy, traffic ahead
Are you serious?-data evaluation-decision on event
Data Trust
• Not adaptive to situation changes.• Mostly a reactive approach• Can we be more proactive ??
Situation Aware Trust for VANETsSituation Aware Trust for VANETs
Are you kidding?I am on a country road
Hey buddy, traffic ahead
Key properties: protective and predictive building of cryptographic foundation for trustworthy exchange Proactive approach: set trust/security parameters
ahead of time (secure key, unique waveform, etc) Reduce on-line security/trust verification time Enable security/trust in exceptional situations
How to become Situation How to become Situation Aware?Aware?
time place affiliation
Attribute based Trust • Situation elements are encode into attributes• Static attributes (affiliation)• Dynamic attributes (time and place) ……
Dynamic attributes can be predicted
Proactive Trust • establish trust in advance• predict based on mobility and location service
Attributes bootstrapped by social networks
Social Trust • Bootstrap initial trust• Transitive trust relations
Situation?
An attribute based situation example:Yellow Cab AND Taxi AND Seattle Street AND 10-11pm 8/22/08
Security on attribute and policy Security on attribute and policy groupgroupburden is on receiver - must update private key every burden is on receiver - must update private key every hour/street??hour/street??A driver wants to alert taxi of
companyA on Washington Street between 10-11am that there was an accident somewhere nearby
Extension of Attribute based Encryption (ABE) scheme [IEEE S&P 07] to incorporate dynamic access tree Attribute (companyA AND
taxi AND Washington St. AND 10-11am)
Extended ABE Module
Ciphertext
Signature
plaintext
Receivers who satisfy those encoded attributes (have the corresponding private key) can decrypt the message
Attribute based encryptionZheng, can you please use a
graphic vignette to show operation of ABE
Say KSP function (KSP?)ABE like PKI, but no need for
central authority, etc
8
Attributed-Based Attributed-Based Encryption(ABE)Encryption(ABE)
Encrypt Data with descriptive “Attributes”
Users Private Keys reflect Decryption Policies
Based on Identity based Encryption and Secret Sharing, not need for credentials as long as the attributed based policy is known
master-key
CA/PKG
Authority is offline
Encryptw/attributes
9
Access Control via Situation-aware Access Control via Situation-aware Policy TreePolicy Tree
PK=Public Key
MSK=Master Secret Key
SKSarah:“companyA”“10:30am”“Washtington St.”
SKKevin:“companyA”“10: 20 am”“Westwood”
AND
companyA AND
10-11 am Washington St.
Sandra thesender
Authority
SAT Architecture: supporting situation awarenessSAT Architecture: supporting situation awareness
SAT layer
• Perception: communicate & sense environments
• Comprehension: extract & aggregate situations
• Projection: predict & create action profiles
• Assessment: evaluate and adjust trust situationsSupporting and trust layer (STL)
• Security primitive
• Comm. primitive
• Portal manage
Social Trust ModelSocial Trust ModelHow are you?
People like to socializeSocial trust is amplifier
In case of infrastructure failure, e.g., messenger is blocked by traffic
Social network help maintain trust◦ People gang up into communities
◦ Elected Leader is MASTER and constructs policy group (ie, Attribute Tree associated to group)
◦ Mobile users are situation aware
◦ ABE based Authenticate and encrypt
Future work:◦ How to establish social networks securely (eg authentication of
social graph update information)◦ How to incoporate social relations to SAT: social network
provides dynamic attributes in the policy tree.
SummarySummarySituation Aware Trust Architecture
◦ Handles dynamic attribute tree based on situation assessment
SAT architecture components◦ Attribute based trust ◦ Proactive trust◦ Social trust ◦ Architecture enabling the model.
Contribution to VANET: mobile proactive security for trustworthy communication!
Future work: Performance Evaluation of the proposed scheme via simulation and testbed experiments
Thanks for your attentionThanks for your attentionDo NOT rent a cab without SAT
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