Some problems with install fpylll
Developer using Ubuntu >= 20.04
So try on Ubuntu 20.04
pip install git+https://github.com/bitlogik/lattice-attack
pip install git+https://github.com/fplll/fpylll.git
All command try installs not successful both on os windows and Linux
using conda not successful too
conda install -c conda-forge fpylll
all methods include update apt too
sudo add-apt-repository universe
sudo apt update
sudo apt install python3-fpylll
pip install Cython
all fail
remove sagemath and it will work. somehow fpylll clash with sagemath and it does not run properly. removing sagemath will solve your issue. in debian,
#apt remove sagemath
#apt update
then run your lattice_attack.py again.