Challenge Graph Sample Clauses

Challenge Graph. We will argue for the security of ▇▇▇ in the framework of Jafargholi et al. [21], with which we will assume familiarity throughout this section. To do so, we need to view the user-mult game for ▇▇▇ as a game on a graph, then define the challenge graph for group key I∗ as a (modified) subgraph of the whole ▇▇▇ graph. Intuitively, each node i in the ▇▇▇-user-mult graph is associated with: 1. dPRF key ki that is sampled randomly in Step 1 of the SecretGen procedure of the group manager for a node u in τmka, or computed via a dPRF computation on key kj and the old dPRF key kj,old at a child u.c of u (corresponding to node j in the ▇▇▇-user-mult graph) in Step 2 of SecretGen;