PERMISSIONED BLOCKCHAIN AND STATE MACHINE REPLICATION

· There is a natural reason to use state machine replication-based consensus over permissioned blockchains.

· The network is closed, the nodes know each other, so state replication is possible among the known nodes.

· Avoid the overhead of mining – do not need to spend anything (like power, time, bitcoin) other than message passing.

· However, consensus is still required – machines can be faulty or behave maliciously.

Now to ensure that you need to have a kind of consensus algorithm in the system now why do we apply this kind of state machine replication-based consensus algorithm in a permission model in contrast to the challenge response-based consensus model which we applied for the permissionless setting.

· There are certain natural reasons to use state machine-based consensus algorithms over permission blockchain.

· The first reason is that the network is closed so when the network is closed every individual node they know each other.

· State replication is possible among the known nodes.

· If you know that who are your peers, you can always replicate your state machine with the current state to your peers the second thing is that this state machine replication-based scenario it avoids the overhead of mining.

· Mining has a sign over it in terms of the system power that you are using in terms of the time that you are providing and amount of Bitcoin that you are you may apply for this kind of proof of state-based mechanism so or proof of elapsed time best mechanism.

· It is like that either in case of a challenge-response method either you have to spend your physical assets, or you have to spend your digital assets and it will take a certain time to solve that particular challenge.

· That has significant kind of over it in case of a permissionless setting but in case of a permission model because we know the participant each other and in case of a state machine replication you do not have this kind of over it where you must spend your physical asset or some kind of virtual assets rather what you have to do that you have to employ certain kind of message passing algorithm in the system.

· You can avoid the overhead of mining by applying this kind of state machine replication-based method but as I have mentioned that consensus is still required on top of the state machine replication because the machines can be faulty, or they can behave maliciously.