A method of authenticating a unique interaction between a mobile device and a smart tag, the method comprising: receiving at a content server, a request for a content from the mobile device, wherein the request comprises a Tag Unique Identifier TAGID and a first Tag Authentication Cryptogram TAC associated with the smart tag; wherein the first TAC is generated by the smart tag based on a first key K1 and a first counter value C1 upon a read request from the mobile device; and wherein the first counter value C1 changes for every read request from the mobile device; receiving, at an authentication server, an authentication request of the smart tag comprising the TAGID and the first TAC from the content server, determining, at the authentication server, that the interaction between the mobile device and the smart tag occurred and corresponds to a unique event by analyzing the first TAC comprising: generating, at the authentication server, a second TAC based on a second key K2 and a second counter value C2 internally maintained at the authentication server; wherein the second key K2 corresponds to the first key K1 and the second counter value C2 corresponds to the first counter value C1; and wherein the second counter value C2 changes for every authentication request; comparing, at the authentication server, the TAGID with a plurality of TAGIDs stored in a TAGID repository and the first TAC to the second TAC to determine if the smart tag is a valid tag; and in response to determining (i) that the interaction between the mobile device and the smart tag occurred and corresponds to the unique event and (ii) that the smart tag is a valid tag, transmitting a message, from the authentication server, to the content server indicating that the mobile device participated in a unique event and the smart tag is a valid tag; providing, by the content server, the requested content to the mobile device in response to the indication. receiving at a content server, a request for a content from the mobile device, wherein the request comprises a Tag Unique Identifier TAGID and a first Tag Authentication Cryptogram TAC associated with the smart tag; wherein the first TAC is generated by the smart tag based on a first key K1 and a first counter value C1 upon a read request from the mobile device; and wherein the first counter value C1 changes for every read request from the mobile device; receiving, at an authentication server, an authentication request of the smart tag comprising the TAGID and the first TAC from the content server, determining, at the authentication server, that the interaction between the mobile device and the smart tag occurred and corresponds to a unique event by analyzing the first TAC comprising: generating, at the authentication server, a second TAC based on a second key K2 and a second counter value C2 internally maintained at the authentication server; wherein the second key K2 corresponds to the first key K1 and the second counter value C2 corresponds to the first counter value C1; and wherein the second counter value C2 changes for every authentication request; comparing, at the authentication server, the TAGID with a plurality of TAGIDs stored in a TAGID repository and the first TAC to the second TAC to determine if the smart tag is a valid tag; and in response to determining (i) that the interaction between the mobile device and the smart tag occurred and corresponds to the unique event and (ii) that the smart tag is a valid tag, transmitting a message, from the authentication server, to the content server indicating that the mobile device participated in a unique event and the smart tag is a valid tag; providing, by the content server, the requested content to the mobile device in response to the indication. generating, at the authentication server, a second TAC based on a second key K2 and a second counter value C2 internally maintained at the authentication server; wherein the second key K2 corresponds to the first key K1 and the second counter value C2 corresponds to the first counter value C1; and wherein the second counter value C2 changes for every authentication request; comparing, at the authentication server, the TAGID with a plurality of TAGIDs stored in a TAGID repository and the first TAC to the second TAC to determine if the smart tag is a valid tag; and in response to determining (i) that the interaction between the mobile device and the smart tag occurred and corresponds to the unique event and (ii) that the smart tag is a valid tag, transmitting a message, from the authentication server, to the content server indicating that the mobile device participated in a unique event and the smart tag is a valid tag; providing, by the content server, the requested content to the mobile device in response to the indication.