blockchain

 A blockchain , or chain of blocks ^{[ 1 ] , [ 2 ]} , is a technology for storing and transmitting information without a control organ. Technically, it is a distributed database whose information sent by users and internal links to the database are checked and grouped at regular time intervals into blocks, thus forming a chain ^[ 3 ] . The whole is secured by cryptography . By extension, a blockchain is a distributed database that maintains a list of records protected against tampering.or modification by storage nodes ; it is therefore a distributed and secure register of all transactions carried out since the start of the distributed system.

There is an analogy with the Internet network , because in both cases the technologies employ computer protocols linked to a decentralized infrastructure. The Internet allows data packets to be transferred from a “secure” server to remote clients (it is up to recipients to verify the integrity of the data transmitted), while a blockchain allows “  trust  ” to be established between agents distinct from the system ^[ 4 ] . With blockchain technology , the "trusted third party" becomes the system itself: each distributed element of the blockchain contains the elements necessary to guarantee the integrity of the data exchanged (by a cryptographic algorithm).