meowpass

Cats are more complex than dogs.

A phrase-password generator that draws from 16,913 embedded cat names, sprinkles in digits and symbols, scores five candidates with Shannon entropy and a stack of complexity heuristics, and hands you the best one. Pure C11. Single binary. Linux + macOS. White-hat.

Marketing site: https://spacetrucker2196.github.io/MeowPasswordC/

Features

• 16,913 cat names embedded directly in the binary — no data files, no network
• OS-grade randomness (getrandom() / /dev/urandom) with rejection sampling
• Best-of-five candidate selection scored across four metrics
• Catified analysis labels in the CLI (Tail Size, Ball of Yarn Entropy, Mashing Resistance, Shiny Foil Ball Uniqueness, Organic NonGMO Catnip)
• --analyze mode to score any existing string
• --psssst silent mode: copy the winner without ever displaying it
• --update self-updater that checks GitHub Releases
• Clipboard via pbcopy (macOS), xclip, or wl-copy (Linux)
• Pure C11. Zero runtime dependencies.

Build

Make

make
./meowpass

CMake

cmake -B build
cmake --build build
./build/meowpass

Install system-wide

sudo make install

Usage

# default — generate, score, show, hint to copy
meowpass

# tune the recipe
meowpass --numbers 4 --symbols 3 --max-length 30

# silent mode — copy winner to clipboard, print nothing
meowpass --psssst

# audit a string you already have
meowpass --analyze "MyP@ssw0rd!"

# run the test suite
meowpass --test

# self-update
meowpass --update

Flags

Flag	What it does	Range / default
--numbers N	Random digits inserted into the phrase	1–10 · default 1–4
--symbols N	Letter→symbol substitutions	1–10 · default 2
--max-length N	Cap on final password length	15–50 · default 25
--copy	Copy winner to clipboard after display	pbcopy / xclip / wl-copy
--psssst, -p	Silent mode — copy only, never print	—
--analyze, -a S	Score an existing string instead of generating	—
--update	Self-update from GitHub releases	requires curl
--test	Run bundled tests	—
--help, -h	Print help	—

How it works

1. Draw a handful of cat names from the embedded dictionary
2. Join them lowercase into a phrase
3. Randomly capitalize a few characters
4. Insert digits at random positions
5. Substitute symbols for select letters
6. Repeat steps 1–5 five times to produce candidates
7. Score each candidate; emit the one with the lowest (best) composite score

Complexity metrics

Internally these are the standard names; in CLI output they wear catified labels.

Internal	CLI label	What it measures
Shannon entropy	Ball of Yarn Entropy	Bits of information per character
Compression ratio	Mashing Resistance	How repetitive the string is (lower = better)
Pattern complexity	Shiny Foil Ball Uniqueness	Substring uniqueness vs length
Character diversity	Organic NonGMO Catnip	Coverage of lower/upper/digits/symbols
Composite score	Overall Relavency	Weighted blend — lower is better

Requirements

• C11 compiler (gcc or clang)
• Linux or macOS
• Optional: xclip or wl-copy on Linux, or pbcopy on macOS, for --copy
• Optional: curl for --update

Project layout

src/         core C — main, config, password, complexity, random, display, update
src/catnames.c     embedded cat-name dictionary (16,913 entries)
tests/       unit tests run by --test
features/    BDD/behave feature files
docs/        marketing site (GitHub Pages)

License

MIT — see LICENSE.

Author

Jeffrey Kunzelman

Credits

Original Swift implementation: MeowPassword.