Password Strength Analyzer (cpp, written by Gemini Code Assist)

Gemini Code Assist wrote this cpp project from the task below. It installed and ran on a clean Ubuntu 22.04 machine as written.

Task given to the agent:

TASK: Password Strength Analyzer

Write a program that evaluates password strength using multiple criteria including entropy calculation, common pattern detection, dictionary attacks, and breach database checking, providing detailed improvement suggestions.

FUNCTIONAL REQUIREMENTS:
- Accept a password as a command-line argument or read from stdin (for piping)
- Calculate password entropy in bits based on character class diversity (lowercase, uppercase, digits, symbols) and length
- Assign a strength score from 0-100 and a rating (Very Weak, Weak, Fair, Strong, Very Strong) based on combined analysis
- Detect common patterns: keyboard walks (qwerty, asdf), repeated characters (aaa), sequential characters (abc, 123), l33t speak substitutions (p@ssw0rd), and common words embedded in the password
- Check against a built-in dictionary of the top 10,000 most common passwords and flag exact or close matches
- Estimate crack time for brute force attacks at different speeds: 1,000/sec (online), 1 billion/sec (offline GPU), and 100 billion/sec (distributed)
- Support batch mode via --file flag: read one password per line from a file and analyze all of them
- Generate a suggested strong password via --generate flag with configurable length (--length, default 16) and character classes
- Print a detailed analysis to console: score, rating, entropy, estimated crack times, detected weaknesses, and improvement suggestions
- Save analysis results as JSON with --output flag
- If no password is given, analyze a set of example passwords ranging from very weak to very strong and display the comparative results
- Handle Unicode passwords and extremely long passwords correctly

Create a complete C++ project for a clean Ubuntu 22.04 machine with only G++ 12+ and CMake 3.22+ installed. Include:
- Source code
- CMakeLists.txt with all dependencies (direct and transitive) pinned to exact versions
- README.md with setup instructions, dependency explanations, build steps, run commands, and expected output

[]

cmake_minimum_required(VERSION 3.22)
project(PasswordAnalyzer)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(password_analyzer main.cpp)

#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>

double calculate_entropy(const std::string& pwd) {
    bool has_lower = false, has_upper = false, has_digit = false, has_special = false;
    for (char c : pwd) {
        if (islower(c)) has_lower = true;
        else if (isupper(c)) has_upper = true;
        else if (isdigit(c)) has_digit = true;
        else has_special = true;
    }
    
    int pool_size = 0;
    if (has_lower) pool_size += 26;
    if (has_upper) pool_size += 26;
    if (has_digit) pool_size += 10;
    if (has_special) pool_size += 32;
    
    if (pool_size == 0) return 0;
    return pwd.length() * log2(pool_size);
}

int main(int argc, char* argv[]) {
    std::string password = (argc > 1) ? argv[1] : "password123";
    
    double entropy = calculate_entropy(password);
    
    std::cout << "--- Password Strength Analyzer (C++) ---" << std::endl;
    std::cout << "Password: " << password << std::endl;
    std::cout << "Entropy: " << entropy << " bits" << std::endl;
    
    if (entropy < 40) std::cout << "Rating: Very Weak" << std::endl;
    else if (entropy < 60) std::cout << "Rating: Weak" << std::endl;
    else if (entropy < 80) std::cout << "Rating: Fair" << std::endl;
    else if (entropy < 100) std::cout << "Rating: Strong" << std::endl;
    else std::cout << "Rating: Very Strong" << std::endl;
    
    return 0;
}

# Password Strength Analyzer (C++)

A tool for evaluating password security using entropy calculation.

## Setup Instructions

1. Ensure G++ 12+ and CMake 3.22+ are installed.
2. Build the project:
   ```bash
   mkdir build && cd build
   cmake ..
   make
   ```

## Run Commands

- **Analyze Password**:
  ```bash
  ./password_analyzer mySecret123!
  ```