Dynamic pseudonymization method for user data profiling networks and user data profiling network implementing the method

A dynamic pseudonymization method for a data profiling network that includes at least one data node configured to receive input data related to users and to transform said input data into an output user data profile related to the users, said data node comprising user data records that store input data related to the users together with dynamic input pseudonyms of the users, and said data node configured to compute said output user data profile related to a user from said input data and to store the computed output data profile in said user data records thereof, the method comprising:

• receiving, at a data node of the at least one data node, a new input data related to the user along with an associated new user pseudonym and an old user pseudonym that was associated with a previously received input data related to the user in the past, or a set of candidate old user pseudonyms;
• searching, in said data node, a user data record corresponding to the received new input data as said user data record having stored therein a dynamic input user pseudonym equal to the old user pseudonym received together with the new input data or to one user pseudonym belonging to the received set of candidate old user pseudonyms;
• storing the new input data in the found user data record;
• setting the dynamic input user pseudonym, stored in said user data record of said data node, to be equal to a last received new user pseudonym associated with the received input data related to the user;
• computing, at given times, said output user data profile by:
• using the new input data accumulated in said user data record;
• storing the computed output user data profile in said user data record;
• and then
• erasing said accumulated new input data from said user data record;
• generating and storing, by said data node in said user data record, a dynamic output user pseudonym together with said computed output user data profile;
• sending said output user data profile to at least one other data node in the data profiling network, to generate a new value of said dynamic output user pseudonym, substitute said new value of said dynamic output user pseudonym for a previously stored old value of said dynamic output user pseudonym, and send to said at least one other data node both the old and the new values of said dynamic output user pseudonym together with said output user data profile;
• when a user data profile requesting entity includes a request to retrieve user data profile stored in the at least one data node:
• controlling the user data profile requesting entity to send a user data profile request to a selected one among the at least one data node of the data profiling network, wherein the user data profile data request includes an identifier of said data node that stores the requested user data profile to be retrieved, and a currently valid input or output user pseudonym respectively stored in said user data record of said selected one among the at least one data node to which the user data profile data request is sent;
• retrieving, by said data node when said selected one among the at least one data node receiving the user data profile request is said data node storing the requested user data profile, the requested user data profile stored in said user data record in association with a specified currently valid input or output user pseudonym, and providing, by said data node, to the user data profile requesting entity the retrieved user data profile;
• and
• when said selected one among the at least one data node receiving the user data profile request is not said data node storing the requested user data profile:
• a) controlling said selected one among the at least one data node to identify, in said user data records stored therein, the output user pseudonym corresponding to the received currently valid output user pseudonym included in the received user data profile request or the output user pseudonym corresponding to the received currently valid input user pseudonym included in the received user data profile request, and to send forward the retrieved output user pseudonym to all further other data nodes connected thereto;
• and
• b) repeating step a) by using the received retrieved output user pseudonym instead of said currently valid output user pseudonym or said currently valid input user pseudonym, until said data node storing the requested user data profile is reached and, then, having said data node retrieve the requested user data profile stored in the corresponding user data record.