A method of, and apparatus for, the synchronization of a deciphering device operating as a receiver with an enciphering device operating as a transmitter, wherein at the transmitter end between information pulse series at a fixed spacing from one another there are inserted a given number of auxiliary pulses similar to the information pulses. Each inserted auxiliary pulse series is produced from the previously inserted auxiliary pulse series in accordance with a predetermined formation principle. At the receiver end the pulse series transmitted by the transmitter is stored in a storage and the stored pulses compared with comparison pulse series in order to determine coincidence of the stored auxiliary pulser series with the comparison pulse series. The comparison pulse series possess the same number of pulses and are formed according to the same formation principle as the auxiliary pulse series. After determination of coincidence of the comparison pulse series with the stored auxiliary pulse series the latter are separated from the stored information pulse series.