Sharif Digital Repository

Secure communication among members of a group requires a shared cryptographic key. To address this issue, group key agreement and exchange schemes are introduced. In group key exchange schemes, a trusted center generates a shared key for the group and sends it securely to the group members. But in group key agreement schemes, all members of the group are involved in generating group keys. One of the useful ways in these schemes is to use secret sharing to share keys. A public key infrastructure is used to secure the distribution of the shares in secret sharing schemes. As quantum computers threat the classic cryptographic algorithms that are based on the difficulty of factoring large numbers... 

We propose a range-free localization framework in which a network of randomly deployed acoustic sensors can passively use natural acoustic phenomena within its environment to localize itself. We introduce a novel approach for registration of sensors observations which takes advantage of a clustering technique on triplets of associated observations. A Bayesian filtering method is employed to incrementally improve system state estimation as more observations become available. To the best of our knowledge this is the first work done on range-free passive acoustic localization. Furthermore, we have proposed a simple but effective and efficient acoustic detection method which can be used to...