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, [ X ] 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, [ X ] K meaning X modulo K and with α a natural integer parameter such that α ∈ {0, ... , K / p }. <EOS>