leviathan-crypto@0.0.0

web [ demo · source · readme ]

A self-contained browser encryption tool in a single HTML file. Encrypt text or files with Serpent-256-CBC and scrypt key derivation, then share the armored output. No server, no install, no network connection after initial load. The code is written to be read. The Encrypt-then-MAC construction, HMAC input, and scrypt parameters are all intentional examples worth studying.

tamper [ demo · source · readme ]

A crypto attack-resilience demo. It runs a real two-party encrypted channel, then lets you attack it: forge a replay and the sequence check rejects it, tamper with a frame and the Poly1305 tag fails. Key exchange uses X25519 with HKDF-SHA256, message encryption uses XChaCha20-Poly1305, and the relay server is a dumb WebSocket pipe that never sees plaintext. The demo deconstructs the protocol step by step with visual feedback for injection and replay attacks. For a real, production-ready secure messenger built on the same library, see COVCOM.

cli [ npm · source · readme ]

Command-line file encryption tool supporting Serpent-256-CBC+HMAC-SHA256, XChaCha20-Poly1305, and AES-256-GCM-SIV via --cipher. A single keyfile works with all three ciphers. The header byte determines decryption automatically. Chunks distribute across a worker pool sized to hardwareConcurrency. Each worker owns an isolated WASM instance with no shared memory. The tool can export its own interactive completions for a variety of shells.

bun add -g lvthn
lvthn keygen --armor -o my.key
cat secret.txt | lvthn encrypt -k my.key --armor > secret.enc

kyber [ demo · source · readme ]

Post-quantum cryptography demo simulating a complete ML-KEM key encapsulation ceremony between two browser-side clients. A live wire at the top of the page logs every value that crosses the channel; importantly, the shared secret never appears in the wire. After the ceremony completes, both sides independently derive a symmetric key using HKDF-SHA256 and exchange messages encrypted with XChaCha20-Poly1305. Each wire frame is expandable, revealing the raw nonce, ciphertext, Poly1305 tag, and AAD.

jwt [ demo · source · readme ]

Classical and post-quantum JSON Web Token signing demo in a single self-contained HTML file. It signs the same claims across eleven algorithms: EdDSA and ES256, the post-quantum ML-DSA and SLH-DSA families, and the leviathan hybrid composites. Every algorithm runs through one uniform path on the Sign suite API, with no per-algorithm branching. The token renders with its three segments color-coded and a live byte readout, so the cost of quantum resistance is visible: the same token grows from about 220 bytes under Ed25519 to past 66 kilobytes under SLH-DSA-SHAKE-256f. Tamper with the payload and verification rejects it, because the signature covers the original bytes.

COVCOM [ demo · source · wiki ]

Covert communications app suite for private group conversations. Invite, talk, close the client, and the chat vanishes. Every message is encrypted with XChaCha20 and signed with Ed25519. A BLAKE3 fingerprint on each key allows peers to verify one another. SPQR's manual and epoch ratchets add forward secrecy, while post-quantum ML-KEM-768 encapsulation keeps recorded communications unreadable and secure against future cryptanalysis.