The invention relates to a decoding method for a probabilistic anti-collusion code aiming to identify at least one sequence of the code present in a multimedia content having served in the creation of an illegal copy of the multimedia content, this method comprising a step of selection of the collusion strategy used to constitute the illegal copy from among a set of collusion strategy models. In addition, the invention relates to a method for filtering sequences of a probabilistic anti-collusion code for the decoding of this code aiming to identify at least one sequence of the code present in a multimedia content having served in the creation of an illegal copy of the multimedia content comprising a step of selection of a sub-group of the smallest possible sequences of code containing at least one sequence present in a multimedia content having served in the creation of the illegal copy by comparing for each sequence of the code and for a selected given symbol index, the symbol of the sequence of the code with the symbol of the sequence contained in the illegal copy.