Method for implementing and managing secure communications, comprising the steps of: a) providing at least one first communicating means having transceiving functions for analog and/or digital signals; b) providing a programmable computer device having transceiving functions for analog and/or digital signals; c) setting up a first communication channel, via said first communicating means, between said programmable computer device and a similar device designed to receive transmissions coming from said programmable computer device; and d) exchanging arbitrary numerical sequences, in the form of analog and/or digital signals, between said first communicating means and said programmable computer devices via said first communication channel, where said first communication channel between said first communicating means and said programmable computer device has limited frequency bandwidth, and in that said analog and/or digital signals are modulated to be carried via said first communication channel, wherein: e) information, data and/or commands are exchanged via said first communication channel between said programmable computer devices and said first communicating means in order to manage secure communication processes comprising one or more among handshaking processes for the creation of secure channels, processes to deliver keys, certificates, cryptographic material and pre-shared secrets in general, provisioning processes of applications and devices, one- or multi-factor authentication and/or authorization processes, local and remote access processes to access computer systems, contract signing processes through advanced electronic signature and digital and/or qualified electronic signature also remotely, transactions and payments also compliant with the standard PSD2 and secure transmitting and receiving processes to transmit and receive messages, data, information, commands and notifications, and wherein: f) said first communication channel transmits and/or receives the aforesaid modulated signals, so that they can be carried via digital and/or analog audio communicating means, where said modulation comprises mapping the single bits of the arbitrary numerical sequence in order to produce an elementary baseband signal, said elementary baseband signal being subsequently processed through signal analog processing and/or digital processing techniques and centered in the frequency range most suitable for the communicating means, characterized in that the limited frequency bandwidth is generated in such a manner capable to be carried within an analogue and/or digital pre-existing communication channel, including a pre-existing video communication channels and voice channel even compressed with a vocoder, and/or a physical medium. a) providing at least one first communicating means having transceiving functions for analog and/or digital signals; b) providing a programmable computer device having transceiving functions for analog and/or digital signals; c) setting up a first communication channel, via said first communicating means, between said programmable computer device and a similar device designed to receive transmissions coming from said programmable computer device; and d) exchanging arbitrary numerical sequences, in the form of analog and/or digital signals, between said first communicating means and said programmable computer devices via said first communication channel, where said first communication channel between said first communicating means and said programmable computer device has limited frequency bandwidth, and in that said analog and/or digital signals are modulated to be carried via said first communication channel, wherein: e) information, data and/or commands are exchanged via said first communication channel between said programmable computer devices and said first communicating means in order to manage secure communication processes comprising one or more among handshaking processes for the creation of secure channels, processes to deliver keys, certificates, cryptographic material and pre-shared secrets in general, provisioning processes of applications and devices, one- or multi-factor authentication and/or authorization processes, local and remote access processes to access computer systems, contract signing processes through advanced electronic signature and digital and/or qualified electronic signature also remotely, transactions and payments also compliant with the standard PSD2 and secure transmitting and receiving processes to transmit and receive messages, data, information, commands and notifications, and wherein: f) said first communication channel transmits and/or receives the aforesaid modulated signals, so that they can be carried via digital and/or analog audio communicating means, where said modulation comprises mapping the single bits of the arbitrary numerical sequence in order to produce an elementary baseband signal, said elementary baseband signal being subsequently processed through signal analog processing and/or digital processing techniques and centered in the frequency range most suitable for the communicating means, characterized in that the limited frequency bandwidth is generated in such a manner capable to be carried within an analogue and/or digital pre-existing communication channel, including a pre-existing video communication channels and voice channel even compressed with a vocoder, and/or a physical medium.