Method for monitoring the integrity of a physical object, wherein - the object is suitable for communicating with a server via a communication network, - a unique identifier is assigned to the object, - predetermined physical properties of the object form a digital fingerprint of the object, and - the object has an electronic system comprising a memory device, wherein the electronic system is suitable for ascertaining the digital fingerprint of the object on request, - a public cryptographic key (pubK) of the server is stored in the memory device of the electronic system, the digital fingerprint of the object is stored in the server device, and wherein the method is characterized in that: - the object receives a request from the server device via the communication network, said request comprising a digital character string, - the electronic system of the object - captures the digital fingerprint of the object in response to the received request, - combines the captured digital fingerprint with a digital secret, which is known to the server and is stored in the memory device, and with the received character string to form a response, and - the object transmits the response via the communication network to the server device for evaluation, wherein the response is encrypted before the transmission to the server device with public key (pubK) of the server device, - the server device receives the encrypted response and - combines the fingerprint stored in the server device with the secret known to the server device and with the character string that the server device sent to the object with the request (Al), - encrypts this combination with the public key (pubK), which has also used the object for the encryption of the response, and - checks whether the result of this encryption is identical to the encrypted response, whereby the integrity of the object is determined. - the object is suitable for communicating with a server via a communication network, - a unique identifier is assigned to the object, - predetermined physical properties of the object form a digital fingerprint of the object, and - the object has an electronic system comprising a memory device, wherein the electronic system is suitable for ascertaining the digital fingerprint of the object on request, - a public cryptographic key (pubK) of the server is stored in the memory device of the electronic system, the digital fingerprint of the object is stored in the server device, - the object receives a request from the server device via the communication network, said request comprising a digital character string, - the electronic system of the object - captures the digital fingerprint of the object in response to the received request, - combines the captured digital fingerprint with a digital secret, which is known to the server and is stored in the memory device, and with the received character string to form a response, and - captures the digital fingerprint of the object in response to the received request, - combines the captured digital fingerprint with a digital secret, which is known to the server and is stored in the memory device, and with the received character string to form a response, and - the object transmits the response via the communication network to the server device for evaluation, wherein the response is encrypted before the transmission to the server device with public key (pubK) of the server device, - the server device receives the encrypted response and - combines the fingerprint stored in the server device with the secret known to the server device and with the character string that the server device sent to the object with the request (Al), - encrypts this combination with the public key (pubK), which has also used the object for the encryption of the response, and - checks whether the result of this encryption is identical to the encrypted response, whereby the integrity of the object is determined. - combines the fingerprint stored in the server device with the secret known to the server device and with the character string that the server device sent to the object with the request (Al), - encrypts this combination with the public key (pubK), which has also used the object for the encryption of the response, and - checks whether the result of this encryption is identical to the encrypted response, whereby the integrity of the object is determined.