Method for confidentially processing data of a vehicle

A method for confidentially processing data of a vehicle, the data being transmitted by an on-board gateway of the vehicle to an access point of a network external to the network and a processing result being transmitted to a server of a service provider, the service provider having generated a private key-public key pair of a homomorphic encryption asymmetric cryptosystem, the method comprising:

• the vehicle generating a secret key of a symmetric encryption cryptosystem and encrypting said secret key by means of the homomorphic encryption public key;
• the vehicle encrypting said data by means of the symmetric encryption secret key;
• the vehicle transmitting the homomorphically encrypted secret key as well as the data thus encrypted to the access point, said access point performing a second encryption of the data thus encrypted, by means of the homomorphic encryption public key, to obtain doubly encrypted data and then, by means of the homomorphically encrypted secret key, a decryption of the doubly encrypted data in the homomorphic domain, to obtain homomorphically encrypted data, and transmitting the homomorphically encrypted data to a computing platform;
• and
• the computing platform performing, in the homomorphic domain, the confidential processing of the data received from the access point and transmitting the processing result, in homomorphically encrypted form, to the server of the service provider.