🔐 Rust Password Generator

A secure, flexible, and user-friendly password generator written in Rust.
This tool allows you to generate strong, random passwords with customizable options, calculate their entropy, and assess their strength.

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✨ Features

• Interactive mode: Answer prompts in your terminal to generate passwords step by step.
• Command-line mode: Use CLI arguments for quick, scriptable password generation.
• Customizable character sets: Choose lowercase, uppercase, digits, symbols, or any combination.
• Multiple password generation: Generate one or many passwords at once.
• Entropy calculation: See the entropy and strength classification for each password.
• Modular codebase: Easy to extend and maintain.

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🚀 Getting Started

Prerequisites

• Rust (edition 2021 or newer)

Build & Run

Clone the repository and build the project:

git clone https://github.com/yourusername/rust-password-generator.git
cd rust-password-generator
cargo build --release

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🛠️ Usage

🖥️ Interactive Mode

Simply run:

cargo run

You will be prompted for:

• Password length
• Number of passwords to generate
• Whether to include lowercase, uppercase, digits, and symbols

Example session:

rust-password-generator - Secure password generator CLI
(Interactive mode)
Enter password length (default 16): 20
Enter number of passwords to generate (default 1): 2
Include character sets? (y/n, default: y)
Lowercase letters? y
Uppercase letters? y
Digits? y
Symbols? n

Pass 1:
yQw8z2Xv9pLm4sRt1uIo

Pass 2:
aB3dE5fG7hJ9kL1mN2pQ

Password 1: entropy = 94.60 bits (Strong)
Password 2: entropy = 94.60 bits (Strong)

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⚡ Command-Line Mode

You can also generate passwords directly using CLI arguments:

cargo run -- --length 20 --symbols --count 3

Available options:

• --length <LENGTH>: Length of each password (default: 16)
• --lowercase / --no-lowercase: Include/exclude lowercase letters (default: include)
• --uppercase / --no-uppercase: Include/exclude uppercase letters (default: include)
• --digits / --no-digits: Include/exclude digits (default: include)
• --symbols / --no-symbols: Include/exclude symbols (default: exclude)
• --count <COUNT>: Number of passwords to generate (default: 1)

Example:

cargo run -- --length 12 --no-symbols --count 2

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📊 Entropy Calculation

For each generated password, the program calculates its entropy using the formula:

entropy = password_length × log2(charset_size)

• password_length: Number of characters in the password
• charset_size: Number of unique characters available for generation

Strength classification:

• 🟥 Weak: < 40 bits
• 🟨 Medium: 40–60 bits
• 🟩 Strong: > 60 bits

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📝 Example Output

Pass 1:
A1b2C3d4E5f6

Pass 2:
G7h8I9j0K1l2

Password 1: entropy = 71.51 bits (Strong)
Password 2: entropy = 71.51 bits (Strong)

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⚠️ Security Notice

• Generated passwords are displayed in clear text in your terminal.
  Ensure your environment is secure and do not share your screen when generating sensitive passwords.
• For even greater security, consider adding clipboard support or file output.

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📄 License

This project is licensed under the MIT License.

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👤 Author

Created by Franciszek Tokarek.