A method for processing telegrams in an automation network comprising a plurality of network subscribers, wherein at least one network subscriber is embodied as a master subscriber and at least one network subscriber is embodied as a slave subscriber, wherein the master subscriber is embodied to output telegrams to the at least one slave subscriber, wherein the master subscriber is embodied to at least partially encrypt the telegrams in each case, wherein the at least one slave subscriber comprises an input port, a receiving logic connected to the input port, a decryption unit connected to the receiving logic and a processing unit embodied to process telegrams on the fly and connected to the decryption unit and the receiving logic, wherein the receiving logic is embodied, in the event that a telegram at least partially encrypted by the master subscriber is present at the input port of the at least one slave subscriber, to forward the at least partially encrypted telegram directly to the decryption unit, wherein the decryption unit is embodied to decrypt an encrypted portion of the at least partially encrypted telegram on the fly with the aid of a key, that is in parallel to the continued receipt of the at least partially encrypted telegram, and to forward it to the processing unit, wherein the processing unit is embodied to process the decrypted portion of the at least partially encrypted telegram on the fly, wherein the receiving logic is embodied, in the event that a telegram unencrypted by the master subscriber is present at the input port of the at least one slave subscriber, to forward the unencrypted telegram directly to the processing unit, wherein the processing unit is embodied to process the unencrypted telegram on the fly, wherein the at least one slave subscriber comprises an output port and an encryption unit connected to the processing unit and the output port, wherein the at least one slave subscriber is connected to the subsequent slave subscriber via the output port via a data line network, wherein the processing unit is embodied to forward the decrypted part of the at least partially encrypted telegram to the encryption unit, and wherein the encryption unit is embodied to decrypt the encrypted portion of the at least partially encrypted telegram on the fly with the aid of the key and to forward it to the output port. wherein the master subscriber is embodied to output telegrams to the at least one slave subscriber, wherein the master subscriber is embodied to at least partially encrypt the telegrams in each case, wherein the at least one slave subscriber comprises an input port, a receiving logic connected to the input port, a decryption unit connected to the receiving logic and a processing unit embodied to process telegrams on the fly and connected to the decryption unit and the receiving logic, wherein the receiving logic is embodied, in the event that a telegram at least partially encrypted by the master subscriber is present at the input port of the at least one slave subscriber, to forward the at least partially encrypted telegram directly to the decryption unit, wherein the decryption unit is embodied to decrypt an encrypted portion of the at least partially encrypted telegram on the fly with the aid of a key, that is in parallel to the continued receipt of the at least partially encrypted telegram, and to forward it to the processing unit, wherein the processing unit is embodied to process the decrypted portion of the at least partially encrypted telegram on the fly, wherein the receiving logic is embodied, in the event that a telegram unencrypted by the master subscriber is present at the input port of the at least one slave subscriber, to forward the unencrypted telegram directly to the processing unit, wherein the processing unit is embodied to process the unencrypted telegram on the fly, wherein the at least one slave subscriber comprises an output port and an encryption unit connected to the processing unit and the output port, wherein the at least one slave subscriber is connected to the subsequent slave subscriber via the output port via a data line network, wherein the processing unit is embodied to forward the decrypted part of the at least partially encrypted telegram to the encryption unit, and wherein the encryption unit is embodied to decrypt the encrypted portion of the at least partially encrypted telegram on the fly with the aid of the key and to forward it to the output port.