Communication participant of a field bus system, and field bus system.

摘要

Communication participant (1a, 1b, 1c) of a field bus system (2) for transmitting data, comprising a two-stage security layer with a fault safety layer (10), which is designed for this purpose, possible errors in the case of a transmission of data within the field bus system (2), and with an item of information security layer (11), which is designed for this purpose, the data before a manipulation and / or to secure against unauthorized read accesses, wherein the information security layer (11) is adapted, in a transmitter operation of the communication subscriber (1a, 1b, 1c) a encrypt the data to be transmitted and then to carry out an authentication code of the encrypted data to generate, together with the encrypted data is transmitted, and in a firm receiving from the encrypted data received to calculate an authentication code and, for checking the data integrity with the received authentication code and to compare then a decryption of the received data to be carried out, characterized in that the information security layer (11) is arranged, in the transmitter operation, the data to be transmitted in data blocks (100) and the data blocks (100) by means of a block encryption with a defined key to encrypt and in the firm receiving received encrypted data blocks (102) with the same key for decrypting.