This project is a simple User Account Management System written in C++20. It provides functionality for user registration, sign in, password recovery, and password change using a command-line interface.

• Register a new user with login, password, and a secret word.

• Sign in with existing credentials.

• Recover a forgotten password using the secret word.

• Change the password after signing in.

• Uses modern C++20 features.

• Minimal and clean I/O system.

• Lightweight with no external dependencies.

  🛠️ Tools and C++ Features Used

This project uses the following C++ features and tools:

-C++20: The project takes advantage of C++20 features, including:

• constexpr functions for compile-time computations.
• Structured bindings for more readable and concise code.
• Concepts: Enforced type constraints using std::concepts.
• Lambda expressions for functional programming style in logic processing.
• std::function for passing function pointers as arguments.
• Nlohmann JSON Library: For handling and parsing JSON formatted user data in a simple way. The nlohmann/json.hpp header is used for serialization and deserialization of user accounts.
• I/O Streams: Extensive use of std::ostream and std::istream for user interaction and input/output management.
• Random Number Generation: Utilized the C++ <random> library to generate dynamic coefficients for password encryption and decryption.

For correct operation you must install the json package if you don't have it.

sudo apt-get install nlohmann-json3-dev

You need a C++20-compatible compiler (e.g., g++-10 or later).

gcc -v
gcc --version

Finally you can run and test the program

make
./authentication