Artifact

This artifact contains the source code and the data to reproduce the results as presented in "A Tale of Snakes and Horses: Amplifying Correlation Power Analysis on Quadratic Maps" at TCHES 2024, Issue 1.

1. Structure

The source code is written in C to exploit power traces to perform the Correlation Power Analysis (CPA) attack and the combined CPA, or Snake attack, as described in the paper for the S-box of Xoodoo and Keccak-p. Additional Python scripts are provided to generate the signal reference values.

2. Hardware Power Traces Source Code

The source code to exploit the power traces is in the folder ./src/.
Each program can be compiled with gcc as

gcc -o keccak-snake keccak-snake.c sort.c -Wall -march=native -O3 -lm -fopenmp
gcc -o keccak-cpa keccak-cpa.c sort.c -Wall -march=native -O3 -lm -fopenmp
gcc -o xoodoo-snake xoodoo-snake.c sort.c -Wall -march=native -O3 -lm -fopenmp
gcc -o xoodoo-cpa xoodoo-cpa.c sort.c -Wall -march=native -O3 -lm -fopenmp

We tested this under Arch linux using gcc 12.2.0, where it compiles without error messages.

The following files have been taken from a publicly available implementation of djbsort:

• sort.c
• int32_minmax_x86.c
• int32_sort.h

3. Additional Resources

Two additional scripts are provided in the folder ./python/:

• Sref.py computes the signal reference values according to Definition 8;
• Sref_reduced.py computes the reduced signal reference values according to Definition 10.

The scripts were tested with Python 3.10.6.

The command lines are:

• Sref.py [-h] n m with the S-box length n in {3, 5} and the number of targeted bits m in {1, n} (to replace n by its integer value),
• Sref_reduced.py [-h] n with the S-box length n in {3, 5}.

4. Contact and Support

Please contact Georg Land ([email protected]) or Anna Guinet ([email protected]) if you have any questions or comments.

5. Licensing

Please see LICENSE for further license instructions.