The invention relates to a method for generating secret codes in an unambiguous manner in order to encode data exchanged between a first user and a second user, for example a node and a terminal of a radiocommunication network, without previous distribution of a secret key, and without using an auxiliary channel, once the node and the terminal have established a controlled radio advantage in relation to all non-authorised third parties. The method is particularly based on a specific implementation of unambiguous and secret code diagrams, astutely concatenating an external code and an internal code, respectively providing security and reliability in the transmission of data.
