Module permutation 

Vision-4 hash permutation implementation.

Core permutation functions for the Vision-4 cryptographic hash, operating on 4-element states over GF(2^128). Each round applies: S-box → MDS → constants → S-box → MDS → constants.

Functions

b_fwd_transform

Applies forward B-polynomial transformation to all elements in state.

b_inv_transform

Applies inverse B-polynomial transformation to all elements in state.

constants_add

Adds round constants to prevent slide attacks.

linearized_b_inv_transform_scalar

Applies linearized B⁻¹ transformation to a single field element using lookup tables.

linearized_transform_scalar

Applies linearized transformation using precomputed lookup tables for efficiency.

mds_mul

Applies MDS matrix multiplication for optimal diffusion.

permutation

Main Vision-4 permutation function operating on 4-element states.

sbox

S-box operation: batch inversion followed by polynomial transformation.