Password Generator

A secure CLI password generator with HaveIBeenPwned breach checking, k-anonymity privacy preservation, and auto-clearing clipboard support.

🔗 Live demo

Try it in your browser: https://securepassword-generator.streamlit.app

A read-only Streamlit UI over the same code in this repo — generate a password, see its strength, entropy, and estimated crack time, and optionally run the privacy-preserving HaveIBeenPwned breach check. The public demo is rate-limited, takes no file uploads, and stores nothing. See DEPLOY.md for how it's hosted and hardened.

Features

• Cryptographically secure generation — uses Python's secrets module (CSPRNG), not random
• k-anonymity breach checking — only the first 5 chars of the SHA-1 hash are sent to the HIBP API; the full hash never leaves the machine
• Entropy calculation + crack-time estimate — shows how long the password would take to brute-force
• Auto-clearing clipboard — password is wiped from the clipboard after a configurable delay
• In-memory wiping — password variable is deleted and garbage-collected after use
• URL allowlist + HTTPS enforcement — HIBP endpoint is validated before any outbound request
• Rate limiting — enforces a minimum interval between API calls
• Ambiguous character exclusion — optionally strip visually confusing chars (0, O, l, 1, I)
• Two modes — interactive prompt-based mode, and a scriptable CLI flag mode

Installation

git clone https://github.com/MetaMaaz/Password-Generator.git
cd Password-Generator
pip install -r requirements.txt
cp .env.example .env

Usage

Interactive mode

python3 PasswordGenerator.py

Prompts you for letter/symbol/number counts and walks you through the options.

CLI mode

# Generate one 14-char password and copy to clipboard
python3 PasswordGenerator.py --letters 10 --symbols 2 --numbers 2

# Show password on screen, skip breach check
python3 PasswordGenerator.py -l 10 -s 2 -n 2 --show --no-breach-check

# Generate 5 passwords at once (auto-prints all, no clipboard copy)
python3 PasswordGenerator.py -l 8 -n 2 --count 5

# Exclude ambiguous characters
python3 PasswordGenerator.py -l 12 -s 2 -n 2 --no-ambiguous

Flags

Flag	Short	Description
--letters N	-l N	Number of letters
--symbols N	-s N	Number of symbols
--numbers N	-n N	Number of numbers
--count N	-c N	Generate N passwords (default: 1)
--show		Print password to stdout
--no-ambiguous		Exclude 0 O l 1 I
--no-breach-check		Skip HIBP API call
--no-clipboard		Don't copy to clipboard
--help	-h	Show help

Configuration

All thresholds and URLs are driven by .env (see .env.example for defaults):

Variable	Purpose
HIBP_URL	Base URL for HIBP range API
HIBP_ALLOWED_DOMAIN	Allowlisted domain for URL validation
HIBP_TIMEOUT_SECONDS	Socket timeout for HIBP requests
STRONG_MIN_LENGTH / STRONG_MIN_SYMBOLS / STRONG_MIN_NUMBERS	Thresholds for "Strong" rating
MEDIUM_MIN_LENGTH	Threshold for "Medium" rating
MIN_PASSWORD_LENGTH	Minimum total character count accepted
GUESSES_PER_SECOND	Assumed attacker speed for crack-time display
AMBIGUOUS_CHARS	Characters stripped when --no-ambiguous is set
CLIPBOARD_CLEAR_SECONDS	Auto-clear delay for clipboard

Running tests

python3 -m pytest tests/

Security design notes

• Why secrets over random — random is seeded from predictable state and is not suitable for security-sensitive output. secrets pulls from /dev/urandom (or the OS equivalent) and is cryptographically sound.
• Why k-anonymity — the HIBP range API lets us check if a password has been breached without ever sending the full hash. We send only the first 5 hex chars of the SHA-1 hash; HIBP returns all suffixes that match, and we check locally.
• Why rate limiting — protects both the user's IP and the HIBP service from accidental request floods.
• Why in-memory wiping — Python doesn't guarantee prompt garbage collection, so we explicitly del the password and call gc.collect() to reduce the window during which the plaintext sits in memory.

License

MIT — see LICENSE.