A method for migration of a blockchain to be replaced, called the first blockchain, to a replacement blockchain, called the second blockchain. The migration method comprises: an initialisation of the second blockchain, the initialisation comprising a generation, in a main blockchain configured to supervise access to the first and second blockchains, of a zone of supervision (250) of the second blockchain; the entry of a user comprising a registration in a directory of users in the main blockchain of a secondary address allocated to this user for the connection to the second blockchain; a generation in the second blockchain of a set of blocks of data corresponding to an image of the first blockchain; a switch of all or some of the users of the first blockchain to the second blockchain so as to prevent registration of transactions in the name of these users in the first blockchain and to permit the registration of transactions in the name of these users in the second blockchain.