A METHOD FOR LOCATING A TAG

The present invention concerns a method for locating a tag (11), the tag (11) having been paired during a pairing step for sharing a secret key between the tag (11) and a first telecommunication terminal (10), the method comprising:i- Sending from the first telecommunication terminal (10) to a remote server (12):- a challenge encrypted by the secret key;- an approximate location indication of the tag (11) defining a search zone,ii- Sending from the remote server (12) to at least one second telecommunication terminal (13) present in the search zone the encrypted challenge;iii- When having received a dynamic message from the tag (11), sending from the at least second telecommunication terminal (13) to the tag (11), the encrypted challenge;iv- Decrypting the encrypted challenge in the tag (11) and sending the challenge to the at least second telecommunication terminal (13);v- Sending from the at least second telecommunication terminal (13) to the first telecommunication terminal (10), through the remote server (12), the challenge and the location of the at least second telecommunication terminal (13);vi- Verifying the challenge at the first telecommunication terminal (10).