Abstract: The invention relates to a method for securing an original software program using a secret, comprising the following steps consisting in: partitioning (1) the software into N elements, N being an integer strictly greater than 1; generating (3) M secure procedures, M being an integer greater than or equal to N, by (i) randomly drawing one function from a library of functions, (ii) selecting one of the N elements or the empty set, and (iii) combining the randomly drawn function and the selected element when the selection is not the empty set, such that each element is combined in a single procedure and all of the elements are combined, each of these steps being performed for each procedure; modifying each procedure by introducing direction tags controlling procedure calls by one another, as well as tags controlling the execution of the elements; and concatenating (9) the M procedures in a secure software program in order to implement the secret.