We want bit-wise transpose hash bijection

[olyutorskii]

We want bit-wise transpose hash bijection

1. fill random bit stream to N×M bit matrix
2. transpose to M×N matrix
3. pick random bit stream from M×N matrix

N ≥ 2 and M ≥ 2.
Either N or M should be a prime number greater than or equal to 3

It's a fast and easy way to bit diffusion.