Original: In cryptography, a permutation box (or P-box) is a method of bit-shuffling used to permute or transpose (rearrange) bits across S-boxes inputs (Maintain diffusion while transposing).
Simplified: In cryptography, a permutation box (or P-box) is a method of bit-shuffling used to permute or transpose (rearrange) bits across S-boxes inputs, maintaining diffusion while transposing.