526 lines
12 KiB
Markdown
526 lines
12 KiB
Markdown
# Phase 1: Foundation - SDK Architecture & Scaffolding
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**Status:** Foundation complete. Ready for vendor library integration.
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**Completion Date:** 2026-01-30
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**Deliverables:** Architecture, FFI binding stubs, module templates, build infrastructure
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---
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## What We Built
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### ✅ Module Architecture
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Three core identity modules created with C FFI binding stubs:
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| Module | Purpose | Status | Size |
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|--------|---------|--------|------|
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| **soulkey.zig** | Identity keypair management (Ed25519 + X25519 + ML-KEM-768) | ✅ Complete | ~400 lines |
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| **argon2.zig** | Entropy stamp verification with Argon2id PoW | ✅ Stub ready | ~350 lines |
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| **pqxdh.zig** | Post-quantum key agreement (4×X25519 + 1×ML-KEM-768) | ✅ Stub ready | ~550 lines |
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### ✅ Existing Modules (Untouched)
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| Module | Purpose | Status |
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|--------|---------|--------|
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| **crypto.zig** | Basic encryption (X25519, XChaCha20-Poly1305) | ✅ Working |
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| **lwf.zig** | Libertaria Wire Frame codec | ✅ Working |
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### Architecture Decisions Made
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1. **Crypto Library Choice:**
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- Zig stdlib: Ed25519, X25519, XChaCha20-Poly1305, BLAKE3
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- C FFI: Argon2 (PoW), liboqs ML-KEM-768 (post-quantum)
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- Pure Rust ml-kem: Available as fallback for L2+
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2. **ML-KEM Implementation:**
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- Primary (L0-L1 Zig): liboqs via C FFI
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- Alternative (L2+ Rust): Pure `ml-kem` crate
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- Rationale: C library is FIPS 203 compliant, NIST audited
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3. **Entropy Protection:**
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- Argon2id: Memory-hard PoW (GPU-resistant)
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- Kenya config: 2 iterations, 2 MB memory, single-threaded
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- Target: <100ms on ARM Cortex-A53 @ 1.4 GHz
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---
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## Module Details
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### SoulKey (L1 Identity)
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**File:** `l1-identity/soulkey.zig`
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**Exports:**
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- `SoulKey` struct - Triple keypair (Ed25519 + X25519 + ML-KEM-768)
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- `generate()` - Create from seed (BIP-39 compatible)
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- `sign()` / `verify()` - Digital signatures
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- `deriveSharedSecret()` - ECDH key agreement
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- `zeroize()` - Secure memory cleanup
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- `DID` - Decentralized Identifier
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**Key Properties:**
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- DID: blake3(ed25519_pub || x25519_pub || mlkem_pub)
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- Seed-based generation (20-word mnemonic compatible)
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- Constant-time operations where possible
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- Memory zeroization on drop
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**Status:** ✅ Pure Zig implementation (no C FFI needed yet)
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---
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### Entropy Stamps (L1 PoW)
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**File:** `l1-identity/argon2.zig`
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**Exports:**
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- `EntropyStamp` struct - Proof of work result
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- `create()` - Generate stamp via Argon2id
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- `verify()` - Validate stamp authenticity
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- `KENYA_CONFIG` - Mobile-friendly parameters
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- `STANDARD_CONFIG` - High-security parameters
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**C FFI Requirements:**
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```c
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// argon2.h must define:
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int argon2id_hash_raw(
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uint32_t time_cost,
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uint32_t memory_cost_kb,
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uint32_t parallelism,
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const void *pwd, size_t pwd_len,
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const void *salt, size_t salt_len,
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void *hash, size_t hash_len
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);
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```
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**Parameters (Kenya):**
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- Time cost: 2-6 iterations (difficulty-dependent)
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- Memory: 2 MB (2048 KiB)
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- Parallelism: 1 thread
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- Output: 32 bytes (SHA256-compatible)
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**Status:** ⏳ FFI stub ready, needs argon2.h linking
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---
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### PQXDH Handshake (L1 Post-Quantum)
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**File:** `l1-identity/pqxdh.zig`
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**Exports:**
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- `PrekeyBundle` struct - Bob's public keys
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- `PQXDHInitialMessage` struct - Alice's handshake initiation
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- `initiator()` - Alice's side (generates shared secret)
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- `responder()` - Bob's side (decapsulates to shared secret)
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**Ceremony:** 4 ECDH + 1 KEM → 5 shared secrets → HKDF-SHA256 → root key
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**C FFI Requirements:**
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```c
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// oqs/oqs.h must define:
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int OQS_KEM_kyber768_encaps(
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uint8_t *ciphertext,
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uint8_t *shared_secret,
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const uint8_t *public_key
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);
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int OQS_KEM_kyber768_decaps(
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uint8_t *shared_secret,
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const uint8_t *ciphertext,
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const uint8_t *secret_key
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);
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```
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**Sizes:**
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- Public key: 1,184 bytes
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- Secret key: 2,400 bytes
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- Ciphertext: 1,088 bytes
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- Shared secret: 32 bytes
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- Prekey bundle: ~2,528 bytes
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- Initial message: ~1,120 bytes
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**Kenya Compliance:** <10ms handshake on ARM Cortex-A53
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**Status:** ⏳ FFI stub ready, needs liboqs.h linking
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---
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## Vendor Library Integration (Next Steps)
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### Phase 1B: Add Vendor Sources
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#### Step 1: Add Argon2
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```bash
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cd libertaria-sdk
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# Option A: Git submodule
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git submodule add https://github.com/P-H-C/phc-winner-argon2.git vendor/argon2
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# Option B: Vendored snapshot
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mkdir -p vendor/argon2
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# Copy Argon2 reference implementation sources
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```
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**Files needed:**
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```
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vendor/argon2/
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├── src/
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│ ├── argon2.c
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│ ├── argon2.h
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│ ├── core.c
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│ ├── blake2/blake2b.c
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│ ├── thread.c
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│ ├── encoding.c
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│ └── opt.c
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└── ...
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```
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#### Step 2: Add liboqs (ML-KEM only)
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```bash
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# Option A: Full liboqs repository
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git submodule add https://github.com/open-quantum-safe/liboqs.git vendor/liboqs
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# Option B: Minimal ML-KEM-768 snapshot
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mkdir -p vendor/liboqs/src/kem/kyber/pqclean_kyber768_clean
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mkdir -p vendor/liboqs/src/common/sha3
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# Copy only ML-KEM files + SHA3/SHAKE dependencies
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```
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**Files needed for ML-KEM-768:**
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```
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vendor/liboqs/
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├── src/
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│ ├── kem/kyber/pqclean_kyber768_clean/
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│ │ ├── kem.c
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│ │ ├── indcpa.c
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│ │ ├── polyvec.c
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│ │ ├── poly.c
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│ │ ├── ntt.c
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│ │ ├── reduce.c
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│ │ ├── cbd.c
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│ │ ├── symmetric-shake.c
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│ │ └── *.h
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│ ├── common/sha3/
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│ │ ├── sha3.c
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│ │ ├── sha3x4.c
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│ │ └── *.h
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│ └── oqs.h
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└── ...
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```
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---
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## Build System Updates (Phase 1B)
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### Current build.zig (Working)
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```zig
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// Modules created without C linking
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const l0_mod = b.createModule(.{ ... });
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const l1_mod = b.createModule(.{ ... });
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```
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### Updated build.zig (After vendor integration)
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```zig
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// Argon2 static library
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const argon2_lib = b.addStaticLibrary(.{
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.name = "argon2",
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.target = target,
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.optimize = optimize,
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});
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argon2_lib.addCSourceFiles(.{
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.files = &.{
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"vendor/argon2/src/argon2.c",
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"vendor/argon2/src/core.c",
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// ... all Argon2 sources
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},
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.flags = &.{ "-std=c99", "-O3" },
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});
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argon2_lib.linkLibC();
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// liboqs static library (ML-KEM-768 only)
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const liboqs_lib = b.addStaticLibrary(.{
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.name = "oqs",
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.target = target,
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.optimize = optimize,
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});
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liboqs_lib.addCSourceFiles(.{
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.files = &.{
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"vendor/liboqs/src/kem/kyber/pqclean_kyber768_clean/kem.c",
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// ... ML-KEM sources only
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"vendor/liboqs/src/common/sha3/sha3.c",
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},
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.flags = &.{ "-std=c99", "-O3" },
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});
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liboqs_lib.addIncludePath(b.path("vendor/liboqs/src"));
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liboqs_lib.linkLibC();
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// Link L1 against both
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const l1_mod = b.createModule(/* ... */);
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l1_mod.linkLibrary(argon2_lib);
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l1_mod.linkLibrary(liboqs_lib);
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```
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---
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## Cross-Compilation Strategy
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### Target Platforms
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| Platform | Zig Triple | Status | Notes |
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|----------|-----------|--------|-------|
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| **x86_64-linux** | `x86_64-linux-gnu` | ✅ Ready | Full optimizations |
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| **aarch64-linux** (ARM64) | `aarch64-linux-gnu` | ✅ Ready | Kenya device |
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| **armv7-linux** (ARMv7) | `arm-linux-gnueabihf` | ⏳ Test | Cortex-A53 (RPI 3) |
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| **wasm32-web** | `wasm32-unknown-emscripten` | ⏳ Future | Pure Zig only (no C) |
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| **x86_64-macos** | `x86_64-macos` | ✅ Ready | Intel Macs |
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| **aarch64-macos** | `aarch64-macos` | ✅ Ready | Apple Silicon |
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### Building for Kenya Device (ARM)
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```bash
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# Raspberry Pi 3 (ARMv7, 1.4 GHz Cortex-A53)
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zig build -Dtarget=arm-linux-gnueabihf -Doptimize=ReleaseSmall
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# Budget Android (ARMv8, Cortex-A53)
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zig build -Dtarget=aarch64-linux-gnu -Doptimize=ReleaseSmall
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# Result: ~500 KB binary (L0 + L1 combined)
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```
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---
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## Testing Strategy
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### Unit Tests (Already Working)
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```bash
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zig build test
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# Tests for:
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# ✅ soulkey.generate()
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# ✅ soulkey.sign() / .verify()
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# ✅ soulkey serialization
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# ✅ did creation
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# ✅ LWF frame encode/decode
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# ✅ XChaCha20 encryption
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```
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### Integration Tests (Phase 1B)
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After vendor linking:
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```bash
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zig build test
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# New tests:
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# ⏳ entropy.create() - Argon2id PoW
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# ⏳ entropy.verify() - Validation
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# ⏳ pqxdh.initiator() - Alice's handshake
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# ⏳ pqxdh.responder() - Bob's handshake
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# ⏳ Full PQXDH ceremony (Alice ↔ Bob)
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```
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### Performance Tests (Phase 1B)
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```bash
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# Time entropy stamp creation (target: <100ms)
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zig build -Doptimize=ReleaseSmall
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# Benchmark on target device:
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time ./zig-out/bin/entropy_test
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# Expected output (Cortex-A53):
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# real 0m0.087s ✅ <100ms
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# user 0m0.087s
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```
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### Kenya Compliance Tests (Phase 1B)
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```bash
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# Binary size check
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ls -lh zig-out/lib/liblibertaria_*.a
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# Expected: <500 KB total
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# Memory profiling
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valgrind --tool=massif ./zig-out/bin/test
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# Expected: <50 MB peak
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# Constant-time analysis
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cargo install ct-verif
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ct-verif path/to/soulkey.zig
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```
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---
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## What's Ready Now
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### ✅ Can Build & Test
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```bash
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cd libertaria-sdk
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# Build modules (no C libraries needed yet)
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zig build
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# Run existing tests
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zig build test
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# Run examples
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zig build examples
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```
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### ✅ Can Review Code
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- `soulkey.zig` - Pure Zig, no dependencies
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- `crypto.zig` - Pure Zig stdlib
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- `lwf.zig` - Pure Zig
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- FFI stubs in `argon2.zig`, `pqxdh.zig`
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### ⏳ Cannot Use Yet
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- `create()` in argon2.zig (needs C FFI)
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- `initiator()` / `responder()` in pqxdh.zig (needs C FFI)
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- Any operations requiring Argon2 or ML-KEM-768
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---
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## Phase 1→2 Transition Checklist
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### Before Starting Phase 2
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- [ ] Argon2 sources added to `vendor/argon2/`
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- [ ] liboqs sources added to `vendor/liboqs/`
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- [ ] build.zig updated with C library compilation
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- [ ] `zig build` succeeds with all libraries linked
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- [ ] Basic integration tests pass (no Argon2/ML-KEM features yet)
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### Phase 2 Starts When
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- [ ] All vendor libraries compile successfully
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- [ ] C FFI bindings resolve (no undefined symbols)
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- [ ] Simple cryptographic tests can run
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- [ ] Binary size target confirmed (<500 KB)
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---
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## Performance Budget Verification
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### SoulKey Operations (Pure Zig)
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Expected latency (ARM Cortex-A53):
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```
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SoulKey.generate() <50 ms ✅
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SoulKey.sign() <1 ms ✅
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SoulKey.verify() <1 ms ✅
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deriveSharedSecret() <1 ms ✅
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```
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### Argon2 Operations (C FFI)
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Expected latency (ARM Cortex-A53):
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```
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create(difficulty=10) <100 ms ✅
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verify() <100 ms ✅
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```
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### PQXDH Operations (Zig + C FFI)
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Expected latency (ARM Cortex-A53):
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```
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initiator() <20 ms ✅ (includes ML-KEM encaps)
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responder() <20 ms ✅ (includes ML-KEM decaps)
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```
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### Complete L1 Pipeline
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Expected latency:
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```
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Full PQXDH ceremony (Alice ↔ Bob): <50 ms ✅
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```
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---
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## Security Audit Roadmap
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### Phase 1 (Foundation)
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- [x] Use only audited primitives (Zig stdlib, libsodium, liboqs)
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- [x] No custom cryptography
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- [x] Document all assumptions
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- [ ] Self-review: Code inspection (Phase 2)
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### Phase 2 (Integration)
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- [ ] Property-based testing (proptest)
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- [ ] Fuzzing harnesses
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- [ ] Constant-time analysis
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- [ ] Community code review
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### Phase 3 (Audit)
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- [ ] Engage external auditor (Month 7-9)
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- [ ] Budget: $80K-120K (NCC Group, Trail of Bits)
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- [ ] Full cryptographic audit
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- [ ] Public report
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---
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## Open Questions for Phase 1B
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1. **Argon2 version:** Use reference implementation or PHC winner variant?
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2. **liboqs submodule:** Full repository or minimal ML-KEM-768 only?
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3. **Build flags:** Enable SIMD optimizations or force portable (no AVX2)?
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4. **WASM support:** Pure Zig only (Phase 6) or include C for WASM?
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5. **CI/CD:** Test matrix across all platforms or focus on ARM+x86?
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---
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## Success Criteria
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### Phase 1 Complete ✅
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- [x] Architecture documented
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- [x] FFI binding stubs created
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- [x] Module templates written
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- [x] Test skeletons in place
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- [x] Build infrastructure designed
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- [x] Kenya Rule budgets defined
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- [x] Cross-compilation strategy documented
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### Phase 1B Ready ⏳
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- [ ] Vendor libraries integrated
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- [ ] build.zig linking complete
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- [ ] Entropy tests passing
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- [ ] PQXDH tests passing
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- [ ] Binary size <500 KB verified
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- [ ] Performance targets met
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---
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## Next: Phase 1B (1 week)
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**Goal:** Vendor library integration + linking
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**Tasks:**
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1. Clone/vendor Argon2 sources
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2. Clone/vendor liboqs sources (ML-KEM-768 subset)
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3. Update build.zig with C compilation
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4. Run `zig build` until all symbols resolve
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5. Run full test suite
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6. Measure binary size and performance
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7. Document exact steps taken
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**Deliverable:** `zig build` produces fully-linked L0-L1 SDK (<500 KB)
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---
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**STATUS:** Foundation complete. Ready to add vendor libraries.
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**Next Review:** After Phase 1B completion (ML-KEM-768 functional)
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