A method for processing a data packet before transmission over a radio communications network as a succession of waveforms transmitted at positions defined by hopping codes, which are time positions or frequency positions. The packet is transmitted over a communications channel of the network by a transmitter node to a destination node. The method includes the following steps performed for each bit of the data packet to be transmitted, referred to as the current bit: calculating a hopping code at least as a function of the value of the current bit and of an encryption key generated by a pseudo-random generator, the encryption key having size greater than the maximum size of a data packet transmitted over the channel; and causing a waveform to be transmitted at the position defined by the calculated hopping code, the transmitted waveform being identical regardless of the value of the current bit.