Latticra Crypto Core

Latticra Crypto Core is an experimental cryptographic sealing core for the Latticra project.

The current implementation uses established open-source cryptographic primitives through libsodium:

• XChaCha20-Poly1305 for authenticated encryption
• BLAKE2b for transcript hashing and seal identifiers
• Ed25519ph for transcript proof/signature verification

Conceptually:

SealΛ(m) := (c, τ, π)

c = XChaCha20-Poly1305(k_msg, nonce, m, AD)
τ = BLAKE2b(AD || c)
π = Ed25519ph(prefix || τ || c)
Δ = BLAKE2b(c || π || τ)

This repository does not claim to introduce a new cryptographic primitive. It is a protocol scaffold built from reviewed primitives.

Repository Layout

.
├── LICENSE
├── README.md
├── Makefile
├── .gitignore
└── lcc.c

Dependencies

Fedora:

sudo dnf install -y gcc make pkgconf-pkg-config libsodium-devel

Build

make

This should produce:

./lcc

Self-test

make check

Expected output:

selftest=ok

Usage

Generate a local key directory:

./lcc keygen keys

This creates:

keys/lcc.key
keys/lcc.sign.pk
keys/lcc.sign.sk

Seal a file:

printf 'Latticra cryptographic core is alive.\n' > msg.txt
./lcc seal keys/lcc.key keys/lcc.sign.sk msg.txt msg.lcc

Inspect a sealed file:

./lcc inspect msg.lcc

Open a sealed file:

./lcc open keys/lcc.key keys/lcc.sign.pk msg.lcc msg.out

Verify the opened file matches the original:

cmp msg.txt msg.out && echo verified

Security Notes

Do not commit secret material.

Never commit:

• keys/
• *.key
• *.sk

The public verification key lcc.sign.pk may be shared. The symmetric key and signing secret key must remain private.

Current Protocol Model

The current LCC seal format contains:

• a compact header
• an XChaCha20-Poly1305 ciphertext
• a BLAKE2b transcript hash
• an Ed25519ph transcript signature
• a derived seal identifier

High-level mapping:

Λ = Latticra domain-separated lattice context
Σ = signature/proof context
κ = symmetric master key
r = XChaCha20 nonce
c = authenticated ciphertext
τ = transcript hash
π = transcript proof/signature
Δ = seal identifier

Status

Experimental research implementation.

Not independently audited.

Not recommended yet for production security boundaries.

Intended Direction

Planned future work may include:

• streaming file encryption
• detached public verification mode
• key rotation
• stronger file format documentation
• test vectors
• fuzzing
• multi-platform CI builds
• post-quantum extension path using standardized PQC primitives