A block interleaving method with a block size K and with N iterations of index j, N being greater than or equal to 1, for interleaving digital data items indexed by a variable k = {0,..., K -1} for positioning input digital data items X in an output sequence made up of output digital data items Y in an order determined by an interleaving law I ( j) ( k) such that Y ( k)= X ( I ( j) ( k)), which method comprises at least: a first step of calculating an intermediate value I 0 j k that for the first iteration, j=1, is the result of applying a first algebraic function f 0 (a, b) modulo K with two variables a and b to the input indices k, a=b=k, such that f 0 ( a, b)=[ -a - pb] K, and, when N>1, for each subsequent iteration j, j=2 to N, is the result of applying the same algebraic function f 0 (a, b) to the input indices k and to an output value I ( j -1) ( k) obtained during the preceding iteration, a=k and b= I ( j -1) ( k); a second step of calculating the output value I ( j) ( k) that, for a given iteration j, is the result of applying a second algebraic function f 1 (a, b) modulo K with two variables a and b to the input indices k and to the intermediate value I 0 j k calculated in the same iteration j, a=k and b = I 0 j k; the first algebraic function f 0 (a, b) and the second algebraic function f 1 (a, b) being linked together so that the output value I ( j) ( k) output from each iteration j is such that: I j k = αp + k + q ⋅ p ⋅ I 0 j k K with q and p natural integer parameters, p being a sub-multiple of K chosen such that its value allows a pattern to be preserved, a pattern to be preserved meaning that the order of p multiplexed data streams, each comprising a partition of K/p data items, is preserved after the interleaving operation, K meaning X modulo K and with α a natural integer parameter such that α ∈ {0,..., K / p}. a first step of calculating an intermediate value I 0 j k that for the first iteration, j=1, is the result of applying a first algebraic function f 0 (a, b) modulo K with two variables a and b to the input indices k, a=b=k, such that f 0 ( a, b)=[ -a - pb] K, and, when N>1, for each subsequent iteration j, j=2 to N, is the result of applying the same algebraic function f 0 (a, b) to the input indices k and to an output value I ( j -1) ( k) obtained during the preceding iteration, a=k and b= I ( j -1) ( k); a second step of calculating the output value I ( j) ( k) that, for a given iteration j, is the result of applying a second algebraic function f 1 (a, b) modulo K with two variables a and b to the input indices k and to the intermediate value I 0 j k calculated in the same iteration j, a=k and b = I 0 j k; the first algebraic function f 0 (a, b) and the second algebraic function f 1 (a, b) being linked together so that the output value I ( j) ( k) output from each iteration j is such that: I j k = αp + k + q ⋅ p ⋅ I 0 j k K with q and p natural integer parameters, p being a sub-multiple of K chosen such that its value allows a pattern to be preserved, a pattern to be preserved meaning that the order of p multiplexed data streams, each comprising a partition of K/p data items, is preserved after the interleaving operation, K meaning X modulo K and with α a natural integer parameter such that α ∈ {0,..., K / p}.