The validity of a certificate will be checked by a validation app available since June 2021 called "čTečka". After having read the QR code from the certificate, the app will connect with the ÚZIS ČR backend and assess the conformity of the data to the recent validation rules. Based on that assessment, the app will then show its result ("valid"/"invalid"). The čTečka app is able to read the unique digital signature of each certificate and thus tell whether the certificate has been forged or not.