Classic encryption, explained line by line
Clean, heavily commented Python that explains each step.
Shift text either way with any key value.
Wrap-around beyond 26 and non-letter characters pass through.
Ideal introduction to how ciphers work.
The complete source is yours to study and change.
Python 3.8 or newer — no third-party packages required
Beginner to intermediate; every file is commented
Personal & educational use; modify freely
It is a source-code bundle meant for learning — you run and modify the Python yourself.
Loops, string handling, modular arithmetic and the basics of cryptography.