AUTHENTICATED KEY ESTABLISHMENT PROTOCOLS –ANALYSIS & DESIGN

Conclusion
INTRODUCTION
New era of Information communication in past few decades Wireless communication New portable devices New applications Challenge – Security to information communication over open network Key technology for security – Cryptography Cryptographic primitives
GROUP KEY ESTABLISHMENT
Popularity of group based applications calls for security in such environment Secure group communication
Each pair of users share a secret key – large number of keys to be maintained All the users share a common secret key – group key establishment
COMMUNICATION MODEL
User1
Contrib1
User2
Contrib2
……………
Usern
Design and analysis of authentication and key establishment protocols Department of CSE, IIT Kharagpur
8
THE WORK
Propose a novel mutual authentication and key agreement which addresses the shortcomings of 3GPP-AKA Analysis of the basic CDMA authentication protocol of 3GPP2. We have pointed out some shortcomings in the existing protocol and have proposed a protocol which alleviates them Secure and efficient two party protocol for communication between the home and visited network
CONTRIBUTIONS OF THIS WORK
Verifiable Group key establishment protocols for heterogeneous networks
VGKA1 – Truly group key agreement protocol. It uses polynomial interpolation VGKA2 – Suitable for heterogeneous environments involving low power devices VGKA-H - Extension to hierarchy, which addresses scalability and efficiency Formal security analysis for all the protocols Each protocol uses less expensive design primitives
A
B
C
gra grb grc gra(rb-rc) grc(rb-ra) grc(rb-ra) Key=grarbr+rarc+rbrc
TWO ROUND PROTOCOLS
Verifiability
U0
k1 k2 k3 k4 k5
U1
U2
U3
U4
U5
Key = F(k1,k2,k3,k4,k5) Can Ui verify that Ki is used in key generation?
KEY ISSUES
Truly contributory group key establishment Protocols for low power devices Existing protocols are not suitable Utilize less expensive design primitives Security analysis Many protocols proposed in the literature were subsequently shown to have weaknesses Formal approach of analyzing the security of protocols
Computationally not efficient Uses multiple rounds Not suitable for resource constrained/heterogeneous environment B grb grarc grbra A Key=grarbrac grcrb grc C
gra
EXISTING PROTOCOLS CONTD..
Use Diffie-Hellman construct but constant number of rounds
The communication requirement is still high Not suitable for resource constrained/heterogeneous environment Very few provide authentication Very few of them give a formal proof of security
Security
Efficiency
Confidentiality Entity Authentication Key freshness Key control Forward secrecy Key confirmation
Number of messages Bandwidth complexity of computations pre-computation?
ORGANIZATION OF THE TALK
IntroduBiblioteka tionBackground Security properties and model
Contribution
Key establishment protocols using one-way hash functions Conference key agreement protocol using polynomial interpolation Scalable group key agreement using hierarchy and cluster Key establishment protocols for mobile networks
MOTIVATIONS
Many protocols proposed in the literature were subsequently shown to have weaknesses Low power devices - existing protocols are not suitable Utilize less expensive design primitives Unlike the two and three party protocols, the group based protocols are still less explored Formal approach of analyzing the security of protocols Security protocols in applications such as mobile networks
A shared secret becomes available to two or more authenticated parties, for subsequent cryptographic use
Designing an authenticated key establishment protocol
AUTHENTICATED KEY ESTABLISHMENT PROTOCOLS – ANALYSIS & DESIGN
Mounita Saha
Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur
CONTRIBUTIONS
Key establishment protocols using one-way hash functions Conference key agreement protocol using polynomial interpolation Key establishment protocols for mobile networks
Design and analysis of authentication and key establishment protocols Department of CSE, IIT Kharagpur
GROUP KEY ESTABLISHMENT PROTOCOL FOR HETEROGENEOUS ENVIRONMENT
Encryption/Decryption One way functions Signatures
CRYPTOGRAPHIC PROTOCOLS
First step