Password Strength Meter

A Python tool that evaluates password strength by calculating entropy and generates secure passwords using either random characters or BIP39 word lists.

Features

• Password Strength Analysis: Calculates entropy in bits to determine password strength
• Entropy-based Security: Recommends passwords with at least 128 bits of entropy
• Dual Password Generation Methods:
  • Random character passwords (letters, numbers, special characters)
  • BIP39 word-based passwords with added complexity
• Smart Character Set Detection: Analyzes which character types are used in your password

How It Works

Entropy Calculation

The tool calculates password entropy based on:

• Character set size (lowercase, uppercase, digits, special characters)
• Password length
• Formula: entropy = length × log₂(character_set_size)

Password Generation

Random Password

• Uses full ASCII character set (letters, numbers, punctuation)
• Minimum length of 16 characters
• Completely random generation for maximum entropy

Word-Based Password (BIP39)

• Uses the BIP39 wordlist (2048 words)
• Randomly capitalizes 1-2 letters per word
• Joins words with random special characters
• Inserts 2-4 random digits at random positions
• Example: aBandon#7fiRe|2gHost&Ocean9

Requirements

• Python 3.6+
• bip39-words.txt file (included in repository)

Usage

python main.py

Follow the prompts:

1. Enter your password to check its strength
2. If entropy is below 128 bits, choose to generate:
   • r for random character password
   • w for word-based password

Security Recommendations

• Strong: ≥ 128 bits of entropy
• Recommended minimum: 16 characters for random passwords
• Word-based: 4 words with modifications provide good memorability and security

Files

• main.py - Main program file
• bip39-words.txt - BIP39 wordlist (2048 words)
• README.md - This file

Example Output

Welcome to the Password Strength Meter!
A strong password should have at least 128 bits of entropy.
let's check your password strength.
Enter your password: password123
The entropy of the password is: 57.00 bits
Your password is too weak. Let's make a new one.
Generate a random password (r) or a words-based password (w)? w
Your new password: 7meTal&Rocket#9sUn|