PassGen 🔐

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Created By: @Nevio-Source

A secure CLI‑based password generator with support for customizable length, Unicode options, and breach checking.

Table of Contents

• Overview
• Features
• Architecture
• Requirements
• Installation
• Flags

Overview

More detailed description of the project.

Motivation: I created PassGen to ensure strong, unpredictable passwords. All planned features aim to maximize security and usability.

Goals:

1. Generate purely random passwords.
2. Avoid known passwords via HIBP checks.
3. Provide flexible Unicode support.

Features

• Choosing Password length
• Choos whether or not using special Unicode characters for the password
• Checking with HIBP if the password is known

Planned Features

• Store the password in a local database

Architecture

The application is a single-file, console-based password generator with a modular functional architecture. While implemented in one class, the program is conceptually split into clearly separated responsibilities.

High-Level Overview

The program consists of four main conceptual layers:

1. User Interface (Console I/O)
2. Entropy & Password Generation
3. Network & External Validation
4. Utility & Cryptographic Functions

These layers interact linearly and do not share mutable global state.

1. User Interface Layer

Responsible for all user interaction via the console.

Includes:

• ASCII banner rendering
• User input handling (password length, unicode selection)
• Output formatting (password display, warnings, status messages)
• Program loop and control flow

This layer does not perform any cryptographic or network logic directly.

2. Entropy & Password Generation Layer

Responsible for generating cryptographically strong randomness and transforming it into a user-readable password.

Key concepts:

• Multiple entropy sources (time-based data + system RNG)
• SHA-256 hashing and HMAC combination
• Deterministic expansion of entropy to arbitrary password lengths
• Mapping raw entropy bytes to a configurable character lexicon

The generator is designed to:

• Avoid predictable patterns
• Scale up to large password sizes
• Remain independent of user input quality

3. Network & External Validation Layer

Responsible for optional online validation of generated passwords.

Includes:

• Network availability check via ICMP (Ping)
• Integration with the Have I Been Pwned (HIBP) API
• k-Anonymity model (SHA-1 prefix querying)

Design goals:

• No plaintext password is ever transmitted
• Graceful degradation when offline
• Non-blocking behavior via async calls

This layer is optional and does not affect password generation itself.

4. Utility & Cryptographic Functions

Low-level helpers used by higher layers.

Includes:

• Cryptographic hash functions (SHA-1, SHA-256, HMAC)
• Secure random number generation
• Time-based entropy helpers
• Formatting and conversion utilities

These functions are stateless and reusable.

Design Characteristics

• Single-process, single-threaded execution model
• Stateless password generation (no persistence)
• Defensive error handling with fallbacks
• Clear separation between generation and validation
• Console-first, platform-agnostic design

This architecture favors clarity, security, and predictability over abstraction or framework complexity.

Requirements

What is required to build or run the project?

• You need Linux or Windows

Installation

Windows

1. Download the Passgen_windows.exe file from the latest release.
2. Start the program by clicking the exe. Or Open Powershell navigate to the folder with the exe and execute

start Passgen_windows.exe

Linux

Binary

1. Download the Passgen_linux from the latest releases
2. Open your terminal and navigate to the folder with the binary then insert the following command

sudo chmod +x Passgen_linux

3. Now you can execute it with

./Passgen_linux

Deb

1. Download passgen_x.x.x_amd64.deb from the latest release
2. Install it with

sudo apt install ./passgen_x.x.x_amd64.deb

3. Now you can execute the program by typing passgen in your terminal

Flags

Defining Length 0-1000

-l <length>

Toggle Unicode

-u 

Skipp HIBP

--no-check 

Show help

--help