Abstract: Passwords consisting of symbols selected from a third set of third symbols, of which a first set constitutes a subset of the first symbols, can be created from a data structure. The method for obtaining this structure comprises the following steps: preparation of a second set of at least two second symbols; creation of a first number of first lists of the first symbols, each list being contained in a third list constituted of the third symbols; creation of a second list of the second symbols, each symbol appearing in that list only once; association of a first list with each symbol of the second list; association of a second symbol to each symbol of the first lists. With this structure (27), a multitude of pseudo-aleatory passwords can be created by means of a code comprising a second symbol, a subcode of at least one first symbol, and a reading path (51) of the symbols in the third lists of the structure, starting from a first symbol found by using the second symbol and the subcode.