After answering the question “why?”, we now move on to the question “where?”, which is: Where is the software? Where is the data? Where is the source code? A very important question in bitcoin, why? Because we said that centralized experiments, that is, experiments controlled by a single entity, in order to be able to respond to a demand and to a search for a digital currency equivalent to gold in terms of privacy and rigidity of the monetary supply, have all failed due to the fragility of a central entity that could easily be stopped and easily shut down If we want to use a metaphor, the best metaphor is BitTorrent. When digital music began to spread, there was one company in particular that responded to people’s need to share music files without any kind of censorship or control, it was called Napster, it was a company that worked very well, it had its own servers that ran a computer program that allowed users to share music files. But Napster was very easy to stop because it had only one company that controlled the code, controlled the servers and controlled the file sharing indexes, it was very easy to fine, to shut down and those servers were very easy to turn off BitTorrent, on the other hand, is an evolution of these sharing systems, it is a so-called completely peer-to-peer evolution, but what does “peer-to-peer” mean? It means that in these new systems, for example BitTorrent file sharing, there is no longer a single company that controls the servers that run a program from a single location, and there is no longer any single point that can be turned off or shut down, stopping the entire system. The difference is basically this: if I shut down Napster’s servers, Napster no longer works and people can no longer use it to share music files, if instead I want to shut down BitTorrent I have to go to the homes of every single user who uses BitTorrent and I have to go and stop them all individually, which as has been shown is often too expensive to implement, making it very difficult to stop decentralized peer-to-peer systems. In short, when we talk about decentralization what we mean is the absence of a central point of attack through which the entire system can be shut down. We no longer have a server, we have many so-called nodes that are absolutely equal to each other, some perhaps more powerful, some less powerful, some more connected, some less connected, some with more or less information, but the key point is that none of these is the single point of failure, the single point of fragility of the entire system. This technology is called decentralization or peer-to-peer, it’s not really a new technology, it wasn’t born with bitcoin, it has nothing to do with the term blockchain. Many today use the term blockchain to indicate the redundancy of information, the distribution of a financial database. In reality, these types of activities are linked to the very origin of the Internet, the Internet itself had a largely decentralized structure at the beginning, with data replicated in newsgroups for example. Another typical example that precedes bitcoin by at least 7 years, thus preceding the concept of blockchain, is precisely the example of files distributed on peer-to-peer systems. From Kazaa, eDonkey and eMule, up to BitTorrent, which has become the standard, and which bitcoin actually recalls if we think about the name. Bitcoin is the attempt to do with money and value, what BitTorrent has done with digital content sharing. Just as we can now share movies or music in a way that is totally impossible to sto on a platform like BitTorrent, the original idea of bitcoin was to be able to give us the same opportunity in the field of value exchange, to be able to exchange value without anyone being able to stop this exchange. When we answer the question “where?”: Where is the computer program? Where are the machines that run this program, Who is in control of these machines? In reality it is also important to check where the source code is, which introduces another very important concept in bitcoin, which is the concept of open source. When, for example, we download Napster, a program provided to us by a centralized company, we can choose to trust this company because we can sue them if something unpleasant happens since this company has a reputation to defend and therefore has reputational, legal and social incentives to maintain certain standards. If we download a computer system from Microsoft, we expect Microsoft to have certain standards, even if they do not exactly meet our expectations. However, in the case of a distributed system such as BitTorrent, there is no longer, and must not exist by design, a single company that we can sue. There is no person responsible for what happens in the software, thus we can’t trust a name like BitTorrent, and we must potentially also be able to actually verify what that computer program does. So it becomes important for a decentralized system like BitTorrent and as also Bitcoin, to be also open source, that is, to allow everyone, not only to store individually and to transmit individually the software itself, the computer program itself, or the data contained in the software: songs in the case of BitTorrent or financial ledgers if we talk about bitcoin, but it is also important that everyone is able to store, share and verify independently the rules of the game, the instructions, the computer source of that program. Each program, when it has to run on a machine, on a computer, is compiled, that is, from a series of instructions that can be read by a human programmer, a series of instructions are created that the machine can instead interpret and execute. In open source code, development takes place by publicly sharing with everyone the source of the information, the source of the program, the source of the code that will be compiled, this means that when we talk about bitcoin, we don’t have to trust someone, for example a bitcoin company that obviously does not exist, we don’t have to trust a name, a brand, symbol, we can and have to, theoretically, verify that the code, the software, does exactly what it claims to do. So when we say that bitcoin works in a certain way, in relation to the inflation rate of this digital gold, or in relation to the protection of our privacy, we do not actually say things we have to trust, but we say things that we can individually verify. There are some conspiracy theories that say that bitcoin actually does this, does that or that bitcoin mining is actually a backdoor of the American NSA to do some complicated calculations, these theories are easily disproved by looking at the code, because all bitcoin users can have a copy of the code. Obviously this creates many differences also in the way in which it is developed, those who work in corporate and commercial IT companies have difficulty understanding how the development and innovation of a system such as bitcoin, where there is no central body of decision, works. There is a team, but this team is basically composed of people that change every year and people that nobody knows. Some of them don’t even have a name, a declared legal identity, they only have a pseudonym, so they use systems such as Git, systems in which everyone can make their own contribution to the code and share it with everyone else, and it is in the end the majority of users who decide which software they want to run and which software they don’t want to run So bitcoin is a truly decentralized software, there is no single company that can be shut down, there is no central server that can be turned off, there is not even a single compiled program that must be certified by someone. Everyone can independently verify and even improve, repair and evolve the source code.