Sharding is an algorithm that allows miners on a blockchain to be divided into groups to confirm transactions simultaneously. This is an alternative to Bitcoin’s model, where all miners compete to confirm a single transaction per time and also find a block per time. The proof of work model as implemented by Bitcoin has made its transaction confirmation and block times longer since there are, now, a higher number of miners competing for block rewards. Sharding is an innovative idea that is in current development for blockchains that operate or planning to operate the proof of stake consensus algorithm like Ethereum- Eth2 and MultiVAC- MTV. 

Ethereum Eth2

Ethereum developers introduced the sharding model to be incorporated into Eth2 still in the test mode soon to be operational. The miners on the blockchain will be divided into shards or groups to confirm transactions allocated to them. After confirmation, the transactions will be submitted to be recorded in the block to be stored by all nodes or miners in the network. This means that the number of transactions to be processed per time will be in the multiples of the number of shards on the blockchain. For example, if a blockchain processes 100 transactions per second, it divides its miners into 10 shards, now it can confirm 1000 transactions in a second. This is a great opportunity but dividing up the miners means that there will be lesser number of miners to confirm a transaction which will be added to a block. It invariably means, hackers will now have to worry less, they only need to sway the miners in a particular shard to double-spend a particular transaction. But Vitalik had a solution for this; what if the miners allocated to a shard are randomized such that different miners confirm transactions on different shards per transaction. So it will be impossible for a hacker to know the miners that are confirming a transaction.

Multidimensional Sharding- MultiVAC

MultiVAC upped the sharding principle by introducing multi-dimensional sharding. The project introduced a unique innovation based on sharding that doesn’t sacrifice speed for security. On MultiVAC blockchain, there are light nodes which are like the users or wallets which make transactions, miner nodes which confirm transactions and storage nodes which store all transactions on a particular shard and the entire blockchain. Light nodes are allocated to a particular shard and unchanged but miners are randomized every few minutes by a randomizer called Verifiable Random Functions, VRF.

The VRF also randomly selects a set of miner nodes to find a block. When a transaction is made by the light nodes, it is sent to the storage node on the shard which stores the unconfirmed transaction and sends it to the miner nodes which are randomly selected to confirm transactions on the shard per time. The confirmed transactions are stored on the block and broadcasted to all storage nodes and miner nodes on the network. The mode of operation of the blockchain might be complex but the innovation ascertains security while scaling the number of transactions per time. 

MultiVAC is still in its test net, the community is waiting earnestly for its main net launch. 

A basic fact for consideration for Sharding

Sharding might not be efficient or reasonable if the number of miners on a network is considerably low in number. Another is that mining pools or mining farms might be the major weakness of shard. The greater the miners in a farm the higher the probability that a higher percentage of miners allocated to a shard will be from a particular location or farm which means the shard is consequently centralized.