Networks Key Distribution Protocols Using KPS

We study cryptographic protocols for the exchange of key information in a computer network consisting of a trusted server T and a set U = {1, 2, …, n} of users sharing individual keys of the symmetric cryptosystem K T,i , i = 1, …, n with it. We denote by 2 U the set of all possible subsets of the set U, by P ⊆ 2 U the set of privileged groups P of users, and by F ⊆ 2 U the set of forbidden user coalitions F. On the server T, by the key pre-distribution scheme (KPS), the preliminary keys (pre-keys) k i of the users i ∈ P are calculated, according to which the users from P can calculate the common working key k P that is not available to users of any alienated coalition F that does not intersect P. The general structure of protocols on which pre-keys k i are computed using upgradable system key information K, delivered to users and implemented for working key computing is substantiated. The protocol uses timestamps providing mutual authentication of users of each privileged group P at a specific moment in time T and security of attacks by members of the forbidden coalition - non-ability to act as a member of a privileged set or impose a compromised key. The protocols inherit the structure and functionality of the underlying protocol with entity authentication using timestamps, extending them to delivering to users the pre-keys and data, allowing to calculate the keys k P for communications within the privileged groups.