Blockchain: an introduction
Aggiornato il: 17 apr 2019
In no small part due to the cryptocurriencies boom blockchain has experienced such a rise to fame that it is now a household name. To understand how this very popular but often misunderstood technology can meet your needs, our blog will host a series of articles dedicated to the theme. In this first article we will introduce it by briefly illustrating its nature and functioning.
What is a blockchain?
A blockchain is a distributed digital ledger where transactions can be recorded in a safe, permanent, and verifiable way. Similarly to a ledger where the various entries are grouped (and ordered) by pages, the transactions recorded in a blockchain are grouped by blocks that are chronologically concatenated to one another. This makes for an unambiguous interpretation of the information stored in a blockchain, as every transaction has its specific address in a block, and every block has a specific position in the chain.
To guarantee the veracity of the information relative to a transaction (and rule out any manipulation by third parties) every transaction is digitally signed with the means of asymmetric cryptography. With such a system any transaction can be referred to its signer with absolute certainty without any chance of compromising the signature, effectively making the information stored in a blockchain both verifiable and attributable.
The distributed nature of the chain addresses the necessity that the recorded transactions be immutable, meaning that it should be impossible for any transaction to be deleted or modified once it has been recorded in a block (and thus in the chain). Every node of a network that manages a blockchain owns a private copy of it, and a common protocol guarantees that there is coherence between the private copies of every node and handles the addition of new blocks. Once a transaction is recorded in a block (and the block is added to the chain), the transaction cannot be altered without altering the block that contains it and all its succeeding blocks. This makes it impossible to alter the data stored in a blockchain unless one has the consensus of the majority of the nodes of the network, sine qua non condition to propagate the altered version of the chain to all the other nodes.
To be continued: applications
Even if its fame is strongly tied with the world of cryptocurrencies, blockchain finds many other purposeful applications in fields where, similarly to cryptocurrencies, it is necessary that information is recorded in a secure, permanent, and verifiable way. In the next article we will delve deeper into this aspect and illustrate in detail the main applications of the technology other than cryptocurrencies.