I’ve been developing Japr750, a symmetric stream cipher engine written in pure Python. My main focus was on optimizing bitwise logic and OOP structure to see how much performance I could squeeze out of Python without using external libraries. Performance: Achieved a 4x speedup after refactoring (~18µs/char). The Challenge: I’ve included a "Public Challenge" in the repository called "Challenge". It uses a randomized internal alphabet and a secret 16-character mapping and three keys I would love your feedback on the implementation or to see if anyone can break the challenge!