A user can establish a data connection to the embedded device using a web browser during the operation of the embedded device, whereupon the web server of the embedded device transmits a random number to the browser. The random number can be encrypted in the browser (e.g. by means of a plug-in) and in the public key of a certificate. The encrypted random number is sent back to the web server of the embedded device and is decrypted by the web server by means of the private key. If the random number and the decrypted value agree, a respective functional block is released. If access to a functional block in a lower level is requested by means of the browser, the previously described authentication is carried out several times after one another using different random numbers. No intervention of the user is required for this purpose.

In accordance with the above example, a symmetrical encryption process can also be used instead of the asymmetrical encryption process. The random number can then be respectively encrypted in the browser and decrypted in the embedded device using the same key.