Method and device for anonymous access control to a collaborative anonymization platform

A method allowing an anonymous access to a collaborative anonymization platform operated by a plurality of operators, each operator having an identical or different number of points of entry PEi to said platform, the method being implemented by computer and comprising the steps of:

• sending out a request for access to a service of the collaborative anonymization platform, for a user having access rights to said platform granted by a first operator OP1;
• receiving a list of data pairs (PEi;
• Keyi) where each data pair contains an identifier of a point of entry PEi to said platform by an operator from amongst the plurality of operators, and contains a random public key Keyi generated for this point of entry;
• generating, in a random manner, a private random value Vx;
• selecting ‘n’ data pairs (PEn, Keyn), where a first data pair (PE1, Key1) has an identifier of point of entry PE1 to said platform by the first operator OP1, and where each other data pair ((PE2, Key2), . . . , (PEi, Keyi), . . . , (PEn, Keyn)) has an identifier of point of entry to said platform by another operator;
• communicating:
• to the first operator via the selected point of entry PE1, a first private key Fx(Vx, Key2, . . . , Keyn), constructed, according to a predefined associative and commutative encryption operation ‘Fx’, from the private random value Vx and from all the public keys associated with the ‘n−1’ other selected points of entry except for the public key Key1 of the point of entry PE1 of the first data pair (PE1, Key1);
• and
• to each operator of each other selected data pair, a private key Fx(Vx, Key1, . . . , Keyi, . . . , Keyn) constructed, according to the encryption operation ‘Fx’, from the private random value Vx and from all the public keys associated with the ‘n−1’ other points of entry except for the public key of said point of entry of each other data pair;
• recording, via the collaborative anonymization platform in a database of private keys, a user private key constructed from the first private key Fx(Vx, Key2, . . . , Keyn) and from the public key Key1 associated with the first point of entry;
• implementing, on the collaborative anonymization platform, an algorithm for verifying private keys, the algorithm operating in an iterative manner between the first operator and each of the other selected operators in order to verify, in the database of private keys, the validity of the user private key;
• and
• validating or refusing access for the user to the collaborative anonymization platform via the point of entry of each operator, depending on the result of the verification.