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Secure Internet Chat

Secure Internet Chat. How to make talking online more secure. Group Key Distribution. Relation to 2 Party Key Exchange Importance 4 of 23 Evans Lectures Lacking Analysis Static/Dynamic Membership. Simple System: Star. n Member Keys, K i 1 Common Key, K Group. 1. 2. 8. 3. S. 7. 4.

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Secure Internet Chat

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  1. Secure Internet Chat How to make talking online more secure.

  2. Group Key Distribution • Relation to 2 Party Key Exchange • Importance • 4 of 23 Evans Lectures • Lacking Analysis • Static/Dynamic Membership

  3. Simple System: Star • n Member Keys, Ki • 1 Common Key, KGroup 1 2 8 3 S 7 4 6 5

  4. Star Join • Establish New Member Key • Update All Group Keys (Multicast) E(KGroup, KNewGroup) 1 E(KGroup, KNewGroup) E(KGroup, KNewGroup) 2 8 3 S E(KGroup, KNewGroup) E(KGroup, KNewGroup) 9 E(K9, KNewGroup) 7 4 6 5 E(KGroup, KNewGroup) E(KGroup, KNewGroup) E(KGroup, KNewGroup)

  5. Star Leave • n-1 Individual Encryptions E(K1, KNewGroup) 1 E(K2, KNewGroup) 2 8 3 S E(K3, KNewGroup) E(K7, KNewGroup) 9 E(K9, KNewGroup) 7 4 6 5 E(K4, KNewGroup) E(K6, KNewGroup) E(K5, KNewGroup)

  6. Basic Rekeying Schemes • N-Party Diffie-Hellman • MIIA • Star Graph • Key Graph

  7. Key Graph SK K2 K2 K1 K1 K1 K1 K0 K0

  8. Key Graph - Member Join SK K2 K2 K1 K1 K1 K1 K0 K0

  9. Key Graph - Member Leave SK K2 K2 K1 K1 K1 K1 K0 K0

  10. Several Members Leave SK K2 K2 K1 K1 K1 K1 K0

  11. Boolean Key Function Minimization K1 K2 K1 K2 K1 K2 K1 K2 X K0 1 1 1 0 1 K0 1 1 = K2 + K1

  12. How to Analyze? • Average Case • Bandwidth • Computation • Storage • Data Models • Simulation

  13. Data Models • Simulator calculates more than net gain

  14. Sample Output

  15. Average Bandwidth/Time

  16. Conclusion • Key Graphs • Boolean Enhanced • Periodic Rekeying

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