  Traditional Blockchain Sharding approaches can only tolerate up to n/3 of
nodes being adversary because they rely on the hypergeometric distribution to
make a failure (an adversary does not have n/3 of nodes globally but can
manipulate the consensus of a Shard) hard to happen. The system must maintain a
large Shard size (the number of nodes inside a Shard) to sustain the low
failure probability so that only a small number of Shards may exist. In this
paper, we present a new approach of Blockchain Sharding that can withstand up
to n/2 of nodes being bad. We categorise the nodes into different classes, and
every Shard has a fixed number of nodes from different classes. We prove that
this design is much more secure than the traditional models (only have one
class) and the Shard size can be reduced significantly. In this way, many more
Shards can exist, and the transaction throughput can be largely increased. The
improved Blockchain Sharding approach is promising to serve as the foundation
for decentralised autonomous organisations and decentralised database.
