How a Blockchain works: validation protocols

In the first article in which we talked about the Blockchain, I explained in a simple way what the characteristics are and how we can define a Blockchain. I would now like to go deeper into the functioning of the validation processes, which are one of the core points of all this technology.


The register of information that is present within a series of nodes is composed of several blocks of data where the information is recorded, which are consolidated within the network after a validation process.

The “actors” of this process are the network of nodes, which are computers connected to the network that have downloaded into their memory the Blockchain network (to give you an idea think that the Bitcoin Blockchain network weighs a massive 269 GB (1), source, then there are the miners that, thanks to the use of very powerful PCs and respecting the validation protocol, check the information before it is consolidated in the blocks. This work done by the miners is remunerated through a fee established from time to time according to the conditions of the network at that particular time.


Therefore, validation protocols are a key and basic element of a Blockchain network and the main ones are:

  • Proof of Works: this is the first protocol born with the Bitcoin network and today is still the most widespread in the panorama of all Blockchain networks. One of the main criticalities of this protocol is that as the network grows, so does the power required to mine a block and this is a limit to the scalability of Blockchain and also involves a very high energy consumption, whose cost can sometimes even go as far as being higher than the fees that the miner receives for his work;


  • Proof of Stake: created to overcome the problem of the previous protocol, an attempt has been made to simplify the mining process in such a way that the time and computing power required are lower. Each time a block is added to the Blockchain network, the creator of the next block is chosen according to established rules and methods (random selection, selection based on seniority, selection based on speed and selection based on vote);


  • There are also a whole series of variants of the validation protocols mentioned above, each of which tries to simplify and iron out some critical issues. Among all of them we can mention the Byzantine Fault Tollerence used by the Stellar platform and based on the “problem of Byzantine generals”: this metaphor refers to the problem of communication between the generals of an army that have to coordinate an attack but can communicate with each other only through messengers that could be corrupted. The validation process foresees that messages can also be corrupted as long as they are no more than ⅓ of the total, which would make the transaction itself invalid.


There would be many other validation protocols to illustrate, but I prefer to stop at these that are the main ones, both not to make the post heavy for the majority of readers, and because my knowledge in this technical field is limited and I can’t explain clearly some existing solutions.


What we have to keep in mind, is that validation protocols are one of the points of Blockchain technology that will continue to have a development, with teams of developers constantly trying to file and improve the critical aspects of one protocol compared to another, let’s think for example of the high energy consumption due to the Bitcoin protocol that has triggered some media campaigns against this technology, which with mass adoption would require a lot of processing power and electricity.


The development is continuous because a validation protocol represents one of the characteristic aspects of one platform compared to another and being able to implement a high-performance and secure protocol will be decisive in determining the best existing Blockchain platform.


(1) aggiornato a Marzo 2020

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