A method for accessing personal data belonging to a data owner, the access policy of a user to these data for a predetermined use being represented by an access token, wherein (a) access tokens are generated by an access token server in accordance with access rules stored in a first database hosted by said server, the access token of said user being identified by a token identifier and transmitted (310, 512), by means of a first transaction, to a first smart contract stored in a blockchain, the first smart contract recording the access token in the blockchain; (b) a terminal of said user transmits, by means of a second transaction, an access authorisation request (350, 521) identified by an authorisation request identifier, to a second smart contract stored in the blockchain, the second smart contract querying the first smart contract and obtaining the access token by providing it with cryptographic elements for authenticating the user, and then determining whether access conditions contained in the token are fulfilled and, if yes, recording the access authorisation into the blockchain; (c) the terminal of said user transmits an access request to a data server, the access request comprising said authorisation request identifier, the data server querying the second smart contract by providing it with said authorisation request identifier, the second smart contract returning to the data server the token corresponding to this request if an access authorisation corresponding to the identifier of the authorisation request is actually recorded in the blockchain, the data server reading personal data stored, in a second personal database at a URL specified in the token, and transmitting them to the terminal of said user. (a) access tokens are generated by an access token server in accordance with access rules stored in a first database hosted by said server, the access token of said user being identified by a token identifier and transmitted (310, 512), by means of a first transaction, to a first smart contract stored in a blockchain, the first smart contract recording the access token in the blockchain; (b) a terminal of said user transmits, by means of a second transaction, an access authorisation request (350, 521) identified by an authorisation request identifier, to a second smart contract stored in the blockchain, the second smart contract querying the first smart contract and obtaining the access token by providing it with cryptographic elements for authenticating the user, and then determining whether access conditions contained in the token are fulfilled and, if yes, recording the access authorisation into the blockchain; (c) the terminal of said user transmits an access request to a data server, the access request comprising said authorisation request identifier, the data server querying the second smart contract by providing it with said authorisation request identifier, the second smart contract returning to the data server the token corresponding to this request if an access authorisation corresponding to the identifier of the authorisation request is actually recorded in the blockchain, the data server reading personal data stored, in a second personal database at a URL specified in the token, and transmitting them to the terminal of said user.