Chapter I. The Proof-of-Stake and a Validator

The Everscale blockchain is a proof of stake blockchain. Proof of stake is a system where people called Validators ensure the correctness of the blockchain by validating blocks. They put down a stake which they would be afraid of losing if they fail to do this, and earn a fee if they succeed. The stake, therefore, is a bond which guarantees their behavior. Conceptually, it’s quite simple, but when it comes to the implementation of such a system, it’s deceptively so. Let us begin at the beginning.

To become a validator of Everscale, you need a computer and you need to have a stake. The Validator puts a stake as collateral and the computer is used to validate blocks. Because Everscale has a high throughput demand it should be a pretty powerful server, but even powerful servers don’t cost too much these days, with prices of around €300 a month being common. The server then runs the blockchain programs, and compares the results of these executed programs with other validators. They then need to agree on the results of these executed programs with each other, or in other words, about a common state of the blockchain. They need to have a consensus. We’ll talk about how the consensus protocol in Everscale works later.

So going back to becoming an Everscale validator, a user needs to deploy a special smart contract and use it to stake some tokens. Then the server we mentioned previously needs to sign a special message and send it to the smart contract saying that this computer is ready to be a validator for that stake. The stake required could be pretty high (right now it runs at around 350,000 Evers and increasing). Obviously we don't want to exclude people from validation, people who don't have these amounts, and want someone with as little as 10 Evers to participate in the network security. So how can they do that? Well, they can deploy a smart contract, put down their stake of 10 Evers, and then ask someone who has a server to Validate their stake.

Let's say there is a market where they can ask some professional validator who runs servers to validate on their behalf, or more precisely, on behalf of their stake. While there are risks associated with this, the protocols described in this paper are precisely there to eliminate them. Nevertheless, always choose your validators wisely.

The validators servers (called nodes) can validate for many such stakes simultaneously. Once the stake has been accepted they are included into a ‘validator set’ by all of the existing validators. If the Validator server is new to the network it will be asked to validate some blocks in advance so other validators can be sure that the server is functioning properly. This is called “qualification mode.” Once they pass that process the new validator can accept real blocks for validation on behalf of any stakes.