1. A Novel Cryptography for Ad Hoc Network Security ► Pi Jian-yong; Liu Xin-song; Wu Ai; Liu Dan; ► 2006 International Conference on Communications, Circuits and Systems Proceedings, Volume 3, 25-28 June 2006 Page(s):1448 - 1452 97/08/28 H.-H. Ou

2. Introduction  Features of Ad Hoc network  Not fixed infrastructure and central administration  The authors' proposed  Offline Trusted Third Party (TTP)  Authentication Code (AC)  Key agreement  Diffie-Hellman 2008/08/282H.-H. Ou

3. The proposed  Initialization  TTP  Private key: V auth  Public Key: Y auth = g V auth mod p  Node identity: m i  Randomly select s i, s i ’,and W i = g si mod p, Q i = g si’ mod p  According to m i = V auth W i + Q i U i mod (p-1) calculate U i by using the extend Euclid alg.  (Wi, Qi, Ui) as the node’s secret private Authentication Code (AC)  Nodes  Verify Y auth Wi g QiUi = g Y auth Wi+QiUi = g mi 2008/08/283H.-H. Ou

4. The proposed  Key agreement  Alice  Randomly select x  X = g x mod p, X’ = g x+Q A U A mod p  (m A, W A, X, X’)   Bob Identity  Yg m B =? Y auth W B Y’ mod p  Session key  K 1 = Y’ x+Q A U A mod p 2008/08/284H.-H. Ou  Bob  Randomly select y  Y = g y mod p, Y’ = g y+Q B U B mod p   (m B, W B, Y, Y’)  Alice Identity  Xg m A =? X auth W A X’ mod p  Session key  K 2 = X’ y+Q B U B mod p  K 1 = g(x+Q A U A )(y+Q B U B ) mod p = K 2