A method of generating a key with perfect security, the method comprising: Preprocessing (610) first source information with a preprocessing channel corresponding to a marginal distribution estimated based on the first source information, Providing a partition of a set of possible preprocessed first source information into a set of subsets, the elements of the subsets being codewords of (n, ε) codes of a composite channel based on statistics of the source (110, 210) and the preprocessing channel based, and the elements of each subset have a constant composition, Determining (622) helper data as an index of the subset comprising the preprocessed first source information, and - determining (632) the key as an index of the preprocessed first source information within the subset comprising the preprocessed first source information.      «

A method of generating a key with perfect security, the method comprising: Preprocessing (610) first source information with a preprocessing channel corresponding to a marginal distribution estimated based on the first source information, Providing a partition of a set of possible preprocessed first source information into a set of subsets, the elements of the subsets being codewords of (n, ε) codes of a composite channel based on statistics of the source (110, 210) and the preprocessing chann...     »