The present invention relates to a vertical synchronizing method and a horizontal synchronizing method of a plurality of chaotic systems and also relates to a method for multichannel communication using synchronized chaotic systems wherein each chaotic system has a pair of a master chaotic device and a slave chaotic device. First chaotic system is synchronized wherein noise or chaotic signal is added to at least one variable of the first master device and the first slave device, respectively, and second chaotic system is synchronized wherein an identical arbitrary variable signal of the first master chaotic device and the slave chaotic device is added to at least one variable of the second master device and the second slave device, and further, by the same manner, the remaining chaotic systems are synchronized. The synchronized chaotic systems are applied to a multichannel system for encryption.