After a few years of development, Vitalik Buterin – creator of the Ethereum network – published the Ethereum Casper Roadmap. This Ethereum Roadmap explains his plan to switch Ether from a Proof of Work (PoW) consensus system to a Proof of Stake (PoS) one. According to the Github post, during the first stage of the process, Ethereum will transition from the PoS to a hybrid form of PoW/PoS. This means that the proof of work system will continue to exist, but additional proof of stake mechanisms will be added every 100 blocks, through a “checkpoint”.
Checkpoint on Ethereum
Checkpoints will allow Ethereum Casper protocol to gradually turn the PoW to a PoS. According to Buterin’s document “The purpose of the PoS consensus process is to “finalize” key blocks called “checkpoints”. Every 100th block is a checkpoint.” To finalize a block, validators with at least two thirds of the total size of the active validator pool need to send “commit” messages for that checkpoint. Once a block is finalized, it cannot go back even if 99% of miners start to support a chain without that block.
Ethereum Casper Activation
The Ethereum Casper algorithm will be activated through a smart contract that “will include functionality that allows anyone to deposit their Ether, specifying a piece of “validation code” (think of this as being kind of like a public key) that they will use to sign messages, and become a validator.” This way, once a user becomes a validator, he/she will be able to send messages to participate in the PoS consensus process. The “size” of a validator within the pool reflects the amount of ether that he/she decides to deposit. The Ethereum Casper smart contract will contain a few rules called “slashing conditions” to award good validators or delete the funds of those who act improperly.
Casper Implementation and Fork
The first Casper stage will take place thanks to a “fork choice rule” that determines what the “canonical chain” is. This is how the replacement for the “longest chain rule” in a Proof of Work consensus process will take place. After this step, a daemon, or an integrated software package will implement the logic needed to be a Casper validator.
Once Ethereum Goes PoS…
The Ethereum Casper algorithm will thus help the network transition from the PoW mechanism to a PoS mechanism gradually. Nevertheless, it will also guarantee that the change is permanent. This is where governance questions on the Ethereum network will probably resurface. Will the PoS make it more likely for those who have DAO type failures to get a bail out? We will have to wait and see.
Click here to read the full Ethereum Casper implementation guide.