An encrypted filesystem to hide your files inside pictures of cats.
A FUSE-ish filesystem that encrypts your data with a password and scatters it across a gallery of valid, viewable cat PNGs. Every block lives inside a picture that still opens as a perfectly normal cat in any image viewer.
A volume is just a directory of those images. Given the directory and the password, kittyFS reconstructs the original files tree, and can serve it over a local WebDAV server, so the volume mounts as a drive and browses like any other folder on Windows, macOS and Linux.
Written in Go. No serious usage intended.
Basic usage example:
kittyfs init # create a volume in ./.kifs
kittyfs mount # serve it at http://localhost:8686/kittyfs/mount also prints the copy-paste command to mount the drive on your OS
Available CLI commands and options:
Usage:
kittyfs [OPTIONS] COMMAND
kittyfs init create an empty volume
kittyfs add SRC [DEST] import a host file into the volume
kittyfs get PATH [OUT] extract a file from the volume
kittyfs ls [PATH] list volume contents
kittyfs rm PATH remove a file from the volume
kittyfs status show volume usage, blocks, encryption
kittyfs mount [--addr host:port] [--basic-auth]
serve the volume as a WebDAV drive
kittyfs cats print the active cover corpus
kittyfs version print the kittyfs version
Common options:
--volume DIR use the volume in DIR instead of .kifs.
--corpus PATH dress blocks as the PNGs in PATH (a directory, walked
recursively, or a single PNG) instead of the embedded cats
Envs:
KITTYFS_PASSWORD - password
KITTYFS_CORPUS - default --corpus path
Requires Go 1.25+
Build with:
make # host binary: ./kittyfs (or kittyfs.exe)
# or
make build-all # Linux, Windows and macOS binaries into dist/kittyFS is built as three decoupled layers, plus a pluggable seam at the bottom:
cmd/kittyfs (CLI + WebDAV) → fs (inodes, dir tree) → blockstore → carrier
- Carrier — The PNG carrier backend
hides a block in a custom private ancillary chunk (
kiFS) inserted right beforeIEND. - BlockStore — carrier-agnostic
Alloc/Read/Write/Free/Flushover a volume directory, with a bump allocator, a free list, and a plaintext superblock in block 0. - fs — inodes and a directory tree on top of the block store, serialized as a JSON index. Whole-file writes only.
Features:
- Encryption: password → Argon2id (salt and params in the superblock) → 256-bit key → AES-256-GCM per block, with a fresh nonce every write. The GCM tag doubles as per-block integrity, so tampering fails authentication instead of returning corrupt data.
- Mounts as a drive, no drivers:
mountserves thefslayer over a local WebDAV server (x/net/webdav), mounted with OS-native clients on Windows, macOS and Linux. - Bring your own cats (BYOC):
--corpuslets you use your own PNGs instead of the embedded cats. Nothing about the corpus is stored in the volume, so reading a volume back never needs it. - Single self-contained binary: pure Go,
CGO_ENABLED=0, cat corpus embedded viago:embed
Known limitations:
- Whole-file writes: no partial or random writes: i.e. changing one byte rewrites and re-encrypts every block of the file.
- Very easily detectable: the
kiFSchunk is trivial to spot. Also, a folder with thousands of cat pictures might raise some question. - No concurrency or crash-consistency: expect neither. Just one coarse global lock, and a kill mid-flush can leave the volume inconsistent.
- 50 MB file cap on a mounted drive on Windows: the Windows WebDAV client
defaults to a 50 MB limit; raise it in the registry for bigger files, or use
add/getfrom cli, which don't go through WebDAV.
This is a toy project, built for playing with fs and steganographic concepts, and for the LOLs.
It is neither audited nor hardened, and not meant for storing anything you actually care about.
Cat pictures were scraped from the awesome https://thesecatsdonotexist.com/ of t04glovern