A method is for securing and verifying an electronic certificate issued by an authority to an owner. The certificate is stored in the memory of a user unit operated by the owner. The user unit transmits all or part of the data of the certificate to the authority. Further, during an initialization phase, the method includes determining, by the authority, a network identifier pertaining to the user unit, and storing, by the authority, the identifier in connection with the data of the certificate. As such, the use of an electronic certificate by individuals other than the owner may be prevented. Further, damages to the owner, in the case of the theft or copying of a certificate, may be avoided.