MKA definition
Examples of MKA in a sentence
There are many options for what a higher-level protocol can do with the shared group key material from the MKA scheme, as stated in the introduction.
Since this is the worst case, we must state the efficiency measures of LBBTs used as MKA trees in terms of m, the maximum number of leaves used throughout its existence.
We note that if a given leaf is marked as removed in a LBBT being used as a MKA tree, it will not have any associated user or secrets and will thus not be considered utilized.
One uses a MKA scheme as follows: Once a group is established by the group manager using create, the manager may call the add, rem, or upd algorithms.
We now describe the cryptographic details of an MKA scheme utilizing a generic tree structure that achieves security with respect to the user-mult game.
Note that the group manager’s state only consists of the current epoch t and the MKA tree for the current epoch t, which we denote as τmka.
The basic properties any MKA scheme must satisfy for this definition are the following: – Correctness even with partially active adversaries: The group manager and all group members output the same group secret in all epochs, once the group members have eventually received all control messages in order (with different messages possibly arbitrarily ordered in between).
However, all such constructions involve a large amount of interaction, requiring many parties to be online, which is undesirable for the MKA and SGM settings.
We use USKE in ▇▇▇ to obtain forward secrecy: Essentially, each node v in the MKA tree τmka for a given epoch t will store a key k which the manager can use to communicate to the users at the leaves of the subtree rooted at v information needed to derive the group secret.
In this section, we formally define the syntax of MKA schemes and introduce a security notion that captures correctness, key indistinguishability, as well as forward secrecy and post-compromise security for group members, even with a partially active and adaptive adversary that can deliver control messages in an arbitrary order for each user.