BoolCrypt is a Python 3 library for vectorial Boolean functions in cryptography. In particular, it provides the following features:

• Represent vectorial Boolean functions in ANF, LUT, univariate polynomials and matrices and change one representation to another.
• List of 3- 4- 5- and 6- bit affine classes and some classes of rotation-symmetric S-boxes.
• Classify a list of S-boxes according to some cryptographic properties.
• Find permutations, rotation-symmetric,reduced-size,... binary and non-binary polynomials.
• Find whether two functions are linear or affine equivalent and count the number of linear or affine self-equivalences.
• Solve functional equations and linear/affine/CCZ equivalence and self-equivalence problems using SAT solvers.

Most of the functions and classes in BoolCrypt contain many examples of their usage in their docstrings, also available in the online documentation.

BoolCrypt was proposed in Implicit White-Box Implementations: White-Boxing ARX Ciphers, and it is a dependency of whiteboxarx.

BoolCrypt requires Python >= 3.7 and SageMath >= 9.1. Although BoolCrypt is meant to be used as a Python library, it can also be used in a Sage shell.

Solving functional equations or equivalence problems requires CryptoMiniSat, which can be installed in SageMath by

sage -i cryptominisat

For some functions in boolcrypt/equivalence.py, BoolCrypt requires sboxU v1.0., but with some modifications described in modifications_sboxU.md. A modified version of sboxU is given in the directory sboxU. Then compile the modified sboxU by

cd sboxU/sboxU_cython
sage setup.py build_ext --inplace