Generating CA-authenticated public keys in ad hoc networks Demo

The demo is a proof of concept of an entity authentication solution defined in [1] that permits nodes in ad hoc networks to generate, on-demand, public/private key pairs whose validity can be verified based on a unique certificate issued by a Certification Authority (CA) during registration in the fixed network. Registration only occurs once and the certificate issued by the CA does not contain any public key but binds an identity to a hash code. This avoids the need to manage the revocation of the certificate in the ad hoc network. In the demo, the entity authentication solution is used by a buying/selling application defined in [2][3] that permits users, in ad hoc networks, to buy or/and sell digital multimedia resources anytime, anywhere and from anybody. Subsequently, we briefly present the authentication solution and the buying/selling application. 2. Entity authentication solution The authentication solution comprises the steps of entity registration, public/private key pair generation and public key validation. These steps are further detailed hereafter. 2.1 Registration In the fixed network, for instance, when a user registers at his network provider, he requests a certificate from a CA as follows. He contacts a CA with his mobile device A in order to obtain a reliable copy of the system parameters: the two one way hash functions h and f as well as the large prime g, KCA the CA’s public key and an integer L. Upon registration or whenever connected to a fixed network A’s mobile device synchronizes its clock; this is important for reasons that become obvious later. When A receives these parameters, it chooses a secret s. Note that s is not stored by A; instead, it is generated from a strong passphrase. Then A generates the check value v