Shadow Crypt

Password-based file encryption with filename obfuscation.

shadow turns files and directories into anonymously named .shadow containers. unshadow restores them. shadows lists them.

Features

Strong cryptography — XChaCha20-Poly1305 authenticated encryption, Argon2id key derivation
Metadata encrypted — filenames, timestamps, and permissions travel inside an encrypted metadata envelope; a directory becomes a single archive that hides even its file count and sizes
Tamper-evident — headers are bound to the ciphertext as AEAD associated data; chunk counters make reordering, truncation, and extension fail authentication
Any size — streaming encryption and decryption with bounded memory
Safe by default — crash-safe atomic writes, no overwrites without --force, no data destroyed before its replacement is verified, path-traversal-proof extraction
Pure Rust — no C or system libraries; builds with Cargo alone

Installation

cargo install shadow-crypt

Or from source: git clone this repository and cargo install --path .

Usage

# Encrypt files (prompts for a password)
shadow notes.txt photos*.jpg

# Encrypt a directory into a single archive
shadow photos/

# Encrypt and delete the originals afterwards
shadow --delete taxes/

# Decrypt
unshadow mzpuTgQmBPJfTAJh.shadow

# List encrypted files with their original filenames (prompts for the password)
shadows

# ...or without decrypting anything (no password needed)
shadows --no-names

For scripting: --password-file, --output-dir, --quiet, shadows --json, and distinct exit codes (see --help).

Key derivation cost is chosen by profile: standard (OWASP-recommended, the default) or paranoid (1 GiB memory, for high-value archives). Files record their parameters, so any profile decrypts with any build. See shadow --profiles.

Documentation

Contributing

Contributions are welcome! Please open issues or submit pull requests on GitHub.

License

Licensed under MIT OR Apache-2.0.

See LICENSE-APACHE and LICENSE-MIT for full license texts.