A blockchain is a list of datasets, known as blocks, which can be continuously expanded. Each of these blocks is chained to the previous block using tamper-proof encryption procedures. If some­one tries to replace a single pearl in this chain, the whole thing will no longer fit together. In this way, the lid is blown off the attempt to tamper with the data. This is guaranteed by the special architecture of the block­chain. Unlike a normal data­base, it is stored locally on all the computers in the net­work. Each user has its own complete copy of the entire chain, and no central owner­ship of the data­base is necessary.