A method and system for processing feedback entries received from software provided by a vendor to an end user machine. The end user machine includes the software, a feedback module, and a database. The feedback module: generates a secret key k(0) and makes the key k(0) known to both the vendor and a user of the software; generates a secret key n(0) and makes the key n0) known to the vendor but not to but not to the user; generates a secret key s(0) and makes the key s(0) known to the user but not to the vendor; generates an encryption Ek0 of an identification tag using the key (k(0); generates a parameter Hn0 such that Hn0=Hash(n(0)∥Ek0); generates a parameter Hs0 such that Hs0=Hash(s(0)∥Ek0); sends Ek0, Hn0, and Hs0 to the database; and sends Ek0 and Hs0 to the vendor.