Ch. 16 – Linear Cryptanalysis

S-Box Analysis Tool

Explore the Linear Approximation Table (LAT) and Difference Distribution Table (DDT) of 4-bit S-boxes. Edit the S-box, load presets, and visualize the cryptographic properties that matter for linear and differential cryptanalysis.

How to use: Edit the S-box values in the grid on the right (click a cell and type a hex value 0–F). Choose preset S-boxes to compare their properties. Toggle between LAT and DDT views. Hover over heatmap cells to see exact values. Adjust the highlight threshold to focus on entries with large bias or high probability.
Low High |bias|

LAT Bias Distribution

S-Box Editor

Not a valid permutation: some output values are repeated or missing.
S-box loaded: Heys

Controls

S-Box Properties

Nonlinearity --
Differential uniformity --
Fixed points --

Best Linear Approximation

Input mask (a) --
Output mask (b) --
Bias --

Best Differential

Input diff (Δx) --
Output diff (Δy) --
Probability --