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Team Challenger. Brian Padalino Sammy Lin Arnold Perez Helen Chen. Group Communication. Authentication Huang, Q. et al “Fast Authenticated Key Establishment Protocols for Self-Organizing Sensor Networks” (2003) International Conference on Sensor Wireless Networks and Applications pp.141.
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Team Challenger Brian Padalino Sammy Lin Arnold Perez Helen Chen
Group Communication • Authentication • Huang, Q. et al “Fast Authenticated Key Establishment Protocols for Self-Organizing Sensor Networks” (2003) International Conference on Sensor Wireless Networks and Applications pp.141
Sensor Networks • Background: • Supports dynamic scenarios, large scale, real-time data processing • Does not require any centralized administration or fixed infrastructure Authentication between sensor nodes and security managers
Sensor Networks • Problems • Sensors have limited power supply and computational resources • Should only send out packets when necessary to help save power • Accurately authenticate with a security manager without using an online centralized database
Sensor Networks • Authentication solutions • A hybrid authentication key establishment protocol • symmetric key cryptographic operations • elliptic curve implicit certificates
Sensor Networks • Implementation • Elliptic Curve Cryptography • Symmetric-Key Operations • Certificates • Certificate contains public key, device ID and certification expiration date, digitally signed • Certificates are acquired before a sensors can join the network
Trust Groups • Keoh, S.L. et al “Towards flexible Credential Verification in Mobile Ad-hoc Networks” (2002) Annual International Workshop on Principles of Mobile Computing, Toulouse, France pp. 58
Key Management • Every device maintains a key ring that contains a list of trusted public keys and their associated trustworthiness level. • Ensures that only trusted public keys are considered when checking assertions. • XML Credential Generator • Used to group the user’s credentials together in order to create a readable credential assertion statement (CAS).
Security Assertion Module • Main functionality is to issue assertions to other users after verifying credentials listed in the CAS successfully. • Verification and Validation Module • Used to determine whether a CAS is authentic and based on authentic credentials. When a user presents his/her CAS together with the corresponding ASSs, the V&V checks the signatures against the key ring to determine whether the assertions can be trusted.
Group Communication • Security • Contributory key agreement • 1) Group Diffie-Hellman key exchange • 2) Key trees
Diffie-Hellman Key exchange Alice picks BK=x Bob Picks BK=y 1 p, , K=x mod p 2 K= y mod p Bob computes K BK = (x mod p)y = xy mod p Alice computes K BK = (y mod p)x = xy mod p The shared secret key
K p =( BK (L) ) K (R) mod p =( BK (R) ) K (L)mod p = K (L) K (R) mod p = f (K (L)K (R)) Key trees <0,0> <1,0> <1,1> <2,0> <2,1> <2,2> <2,3> <3,0> <3,0> <3,6> <3,7>
Problems and Solutions • Join, Leave, Partition and Merge by Updating Current Tree <0,0> <1,0> <1,1> <2,0> <2,1> <2,2> <2,3> <3,0> <3,0> <3,6> <3,7>
Project Idea • Will be implementing system outlined by “Towards Flexible Credential Verification in Mobile Ad-hoc Networks” • Will be adding certificate/assertion revocations and some sort of black listing policy for untrustworthy nodes to increase security of the proposed system.
Project Idea (cont.) • Will be building a game on top of our system to demo what it can do. • Social engineering game geared towards building and losing trust. • Player must try and obtain as much ASS as possible. Then use that ASS to get more ASS.
Papers to be used… • “Towards a human trust model for mobile ad-hoc networks,” Licia Capra • “A certificate revocation scheme for wireless ad-hoc networks,” Claude Crepeau and Carlton Davis • “Trust and establishment of ad-hoc communities,” Sye Long Keoh and Emil Lupu