  This paper presents V-Guard, a new permissioned blockchain that achieves
consensus for vehicular data under changing memberships, targeting the problem
in V2X networks where vehicles are often intermittently connected on the roads.
To achieve this goal, V-Guard integrates membership management into the
consensus process for agreeing on data entries. It binds a data entry with a
membership configuration profile that describes responsible vehicles for
achieving consensus for the data entry. As such, V-Guard produces chained
consensus results of both data entries and their residing membership profiles,
which enables consensus to be achieved seamlessly under changing memberships.
In addition, V-Guard separates the ordering of transactions from consensus,
allowing concurrent ordering instances and periodic consensus instances to
order and commit data entries. These features make V-Guard efficient for
achieving consensus under dynamic memberships with high throughput and latency
performance.
