Part of the mystery
In 2008, when the financial crisis hit, popular mistrust of banks peaked. But how do you bypass them
to make transactions? An anonymous informatics expert (or group of experts), still not identified to
this day, hiding behind the pseudonym of Satoshi Nakamoto, then came up with the idea of a
cryptocurrency: the Bitcoin. A genuine digital currency that can be exchanged peer-to-peer without
going through a “trusted third party”, such as a bank. The transactions are recorded on the personal
computers of each member of the community, constituting so many decentralized ledgers. Movements are
recorded in these “blocks” in unalterable form, and all these blocks form a chain. The term
“blockchain” did not appear until 2013 with the first application projects for areas other than
cryptocurrency, such as stocks and shares or contracts.
Guaranteed integrity
Its very structure of distributed, decentralized ledger guarantees the blockchain a unique safety of
transactions. All the data entrusted to it features, in encrypted form, throughout the whole of
these interconnected blocks. All is recorded in chronological order and can then be verified without
it being possible to change the content or alter the data fraudulently. Each member is the final
guarantor of the integrity of all the data.
“Public” blockchain, “private” blockchain
The public blockchains today mainly concern cryptocurrency transactions. No matter which surfer,
buying for example bitcoins, automatically integrates the chain by creating his own block and thus
becomes, in his turn, the guarantor of the integrity of all of the blocks. The private blockchains,
easier to set up, for example in a company with its partners, is limited to a predefined list of
users with rights of access.
