76d092d4f6
The Vault Creation Flow ASCII showed only manifest.enc as init's encrypted artifact; cmd_init has been writing settings.enc in parallel since the VaultSettings rollout. Update the encrypt step to show both artifacts side-by-side with independent nonces. Below the ASCII, add a short pointer noting that the per-item lifecycle (typed-item envelope, attachment encryption, field-history) lives in crates/relicario-core/ARCHITECTURE.md and reuses the same master_key + XChaCha20-Poly1305 primitives. The doc-audit framing is "this top-level doc could just point at the per-crate docs" — taking that trim path. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
17 KiB
17 KiB
Relicario — Architecture
System Overview
┌──────────────────────────────────────────────────────────────────┐
│ CLIENT DEVICE (trusted) │
│ │
│ ┌─────────────┐ ┌──────────────┐ ┌──────────────────────┐ │
│ │ Reference │ │ Passphrase │ │ relicario-cli │ │
│ │ JPEG │ │ (typed) │ │ or browser ext │ │
│ │ (on disk) │ │ │ │ │ │
│ └──────┬───────┘ └──────┬───────┘ └──────────┬───────────┘ │
│ │ │ │ │
│ ▼ │ │ │
│ ┌──────────────┐ │ │ │
│ │ imgsecret │ │ │ │
│ │ ::extract() │ │ │ │
│ └──────┬───────┘ │ │ │
│ │ │ │ │
│ ▼ ▼ │ │
│ ┌──────────────────────────────┐ │ │
│ │ Argon2id KDF │ │ │
│ │ password = passphrase ‖ │ │ │
│ │ image_secret │ │ │
│ │ salt = vault_salt │ │ │
│ │ → master_key (32 bytes) │ │ │
│ └──────────────┬───────────────┘ │ │
│ │ │ │
│ ▼ │ │
│ ┌──────────────────────────────┐ │ │
│ │ XChaCha20-Poly1305 │◄──────────────────┘ │
│ │ encrypt / decrypt │ │
│ │ (192-bit nonce, 256-bit │ │
│ │ key, 128-bit auth tag) │ │
│ └──────────────┬───────────────┘ │
│ │ │
└─────────────────┼──────────────────────────────────────────────────┘
│
│ git push / pull (HTTPS or SSH)
▼
┌──────────────────────────────────────────────────────────────────┐
│ GIT SERVER (untrusted) │
│ │
│ relicario-vault.git/ │
│ ├── manifest.enc ← opaque ciphertext │
│ ├── settings.enc ← opaque ciphertext │
│ ├── items/ │
│ │ ├── a1b2c3d4e5f6a7b8.enc ← opaque ciphertext │
│ │ └── … │
│ ├── attachments/ │
│ │ └── <item-id>/<aid>.enc ← opaque ciphertext │
│ └── .relicario/ │
│ ├── salt ← 32 bytes (not secret) │
│ ├── params.json ← KDF params (not secret) │
│ ├── devices.json ← device public keys (not secret) │
│ └── revoked.json ← revoked device records (not secret) │
│ │
│ The server sees NOTHING useful. No keys, no plaintext, │
│ no metadata about what's inside. │
└──────────────────────────────────────────────────────────────────┘
Vault Creation Flow
User provides: System generates:
├── carrier JPEG (any photo) ├── image_secret (256-bit random)
└── passphrase (memorized) └── vault_salt (256-bit random)
┌──────────────────┐
carrier JPEG ──────►│ imgsecret │──────► reference.jpg
image_secret ──────►│ ::embed() │ (looks like a normal photo,
│ DCT stego │ carries hidden secret)
└──────────────────┘
┌──────────────────┐
passphrase ────────►│ │
│ Argon2id │──────► master_key (32 bytes)
image_secret ──────►│ (64 MiB, 3 it) │ (held in memory only)
vault_salt ────────►│ │
└──────────────────┘
┌──────────────────┐
master_key ────────►│ XChaCha20- │──────► manifest.enc
empty manifest ────►│ Poly1305 │ settings.enc
default settings ──►│ encrypt (×2) │ (parallel artifacts;
└──────────────────┘ independent nonces)
┌──────────────────┐
│ git init │──────► vault repo
│ git commit │ (ready to push)
└──────────────────┘
Item creation, the typed-item envelope (Item + per-type ItemCore),
attachment encryption, and field-history tracking are not shown above —
they are described in crates/relicario-core/ARCHITECTURE.md.
The flow above covers only the crypto-pipeline shape that vault init
establishes; the per-item lifecycle reuses the same master_key +
XChaCha20-Poly1305 primitives against items/<id>.enc and
attachments/<item-id>/<aid>.enc.
Unlock Flow (every vault operation)
┌──────────────────┐
reference.jpg ─────►│ imgsecret │──────► image_secret
│ ::extract() │ (256 bits)
└──────────────────┘
┌──────────────────┐
passphrase ────────►│ │
image_secret ──────►│ Argon2id │──────► master_key
vault_salt ────────►│ │
└──────────────────┘
┌──────────────────┐
master_key ────────►│ XChaCha20 │──────► plaintext entries
*.enc files ───────►│ ::decrypt() │ (in memory only)
└──────────────────┘
imgsecret DCT Embedding
Input JPEG
│
▼
┌──────────────────┐
│ Decode to RGB │
│ Extract Y │
│ (luminance) │
└────────┬─────────┘
│
▼
┌──────────────────────────────┐
│ Full Image │
│ ┌────────────────────────┐ │
│ │ 15% ┌────────────┐ │ │
│ │margin│ │15% │ │
│ │ │ Central │mar-│ │
│ │ │ 70% │gin │ │
│ │ │ EMBEDDING │ │ │
│ │ │ REGION │ │ │
│ │ └────────────┘ │ │
│ │ 15% margin │ │
│ └────────────────────────┘ │
└──────────────────────────────┘
│
▼
┌──────────────────┐
│ Divide into │
│ 8×8 blocks │
│ Apply 2D DCT │
└────────┬─────────┘
│
▼
┌──────────────────┐
│ For each │
│ selected block: │
│ │
│ QIM embed bits │
│ in positions │
│ 4-15 (mid-freq) │
│ │
│ Repeat secret │
│ 20+ times │
└────────┬─────────┘
│
▼
┌──────────────────┐
│ Inverse DCT │
│ Reconstruct RGB │
│ Save JPEG (Q92) │
└──────────────────┘
│
▼
Output: reference.jpg
(visually identical,
carries 256-bit secret)
Extraction (with crop recovery)
Input JPEG (possibly re-encoded or cropped)
│
▼
┌─────────────────────────┐
│ Try canonical alignment │──── Success ──► image_secret
│ (offset 0,0) │
└─────────┬───────────────┘
│ Fail
▼
┌─────────────────────────┐
│ Search crop offsets │
│ dx, dy: -15% to +15% │
│ step: 8 pixels │
│ (~16,800 candidates) │──── Success ──► image_secret
│ │
│ For each: extract bits, │
│ majority vote, check │
│ confidence ≥ 60% │
└─────────┬───────────────┘
│ All fail
▼
ExtractionFailed error
Encrypted File Format
┌─────────┬────────────────────────┬──────────────────┬──────────────────┐
│ version │ nonce │ ciphertext │ auth tag │
│ 1 byte │ 24 bytes │ N bytes │ 16 bytes │
│ 0x01 │ random per write │ XChaCha20 stream │ Poly1305 MAC │
└─────────┴────────────────────────┴──────────────────┴──────────────────┘
Crate Architecture
┌────────────────────────────────────────────────────────────┐
│ relicario-cli │
│ Filesystem, git (shelling out), terminal I/O, clipboard │
│ │
│ Depends on: relicario-core, clap, anyhow, rpassword, arboard │
└──────────────────────┬─────────────────────────────────────┘
│ uses
▼
┌────────────────────────────────────────────────────────────┐
│ relicario-core │
│ Platform-agnostic: bytes in, bytes out │
│ No filesystem, no network, no git │
│ │
│ ┌──────────┐ ┌──────────┐ ┌─────────┐ ┌────────────┐ │
│ │ crypto │ │ imgsecret│ │ item + │ │ vault │ │
│ │ │ │ │ │ types │ │ │ │
│ │ KDF │ │ DCT │ │ Item │ │ encrypt_ │ │
│ │ encrypt │ │ embed │ │ Manifest│ │ item() │ │
│ │ decrypt │ │ extract │ │ Settings│ │ decrypt_ │ │
│ │ │ │ QIM │ │ Backup │ │ manifest() │ │
│ │ │ │ │ │ Device │ │ ... │ │
│ └──────────┘ └──────────┘ └─────────┘ └────────────┘ │
│ │
│ Consumed by: relicario-cli, relicario-wasm (extension), │
│ relicario-server (pre-receive hook). │
│ Future: JNI/Swift wrappers for Android/iOS. │
└────────────────────────────────────────────────────────────┘
Entropy at Each Attack Scenario
Server breach only: ████████████████████████████ 256+ bits (infeasible)
passphrase + image_secret
Server + stolen image: ████░░░░░░░░░░░░░░░░░░░░░░ ~51 bits (4 diceware words)
passphrase through Argon2id ~7 million years
Shoulder-surfed passphrase: ████████████████████████████ 256 bits (infeasible)
image_secret
Stolen device: ████░░░░░░░░░░░░░░░░░░░░░░ ~51 bits (4 diceware words)
passphrase through Argon2id ~7 million years
Both factors compromised: game over (same as every password manager)