# NOMYO Python Client — Translation Reference

> Target: Port this library to another language. Every class, method, signature, constant, wire format, and error mapping is documented below.

---

## 1. Package Layout

| File (relative to package root) | Purpose |
|---|---|
| `nomyo/__init__.py` | Public exports, version string |
| `nomyo/nomyo.py` | `SecureChatCompletion` — OpenAI-compatible entrypoint |
| `nomyo/SecureCompletionClient.py` | Key mgmt, hybrid encryption, HTTP roundtrip, retries |
| `nomyo/SecureMemory.py` | Cross-platform memory locking + secure zeroing (optional, platform-specific) |

**Python version:** `>= 3.10`
**Build:** `hatchling` (pyproject.toml)
**Dependencies:** `anyio`, `certifi`, `cffi`, `cryptography`, `exceptiongroup`, `h11`, `httpcore`, `httpx`, `idna`, `pycparser`, `typing_extensions`

---

## 2. Public API Surface (`__all__`)

| Export | Type | Source file |
|---|---|---|
| `SecureChatCompletion` | class | `nomyo.py` |
| `SecurityError` | exception | `SecureCompletionClient.py` |
| `APIError` | exception (base) | `SecureCompletionClient.py` |
| `AuthenticationError` | exception (401) | `SecureCompletionClient.py` |
| `InvalidRequestError` | exception (400) | `SecureCompletionClient.py` |
| `APIConnectionError` | exception (network) | `SecureCompletionClient.py` |
| `ForbiddenError` | exception (403) | `SecureCompletionClient.py` |
| `RateLimitError` | exception (429) | `SecureCompletionClient.py` |
| `ServerError` | exception (500) | `SecureCompletionClient.py` |
| `ServiceUnavailableError` | exception (503) | `SecureCompletionClient.py` |
| `get_memory_protection_info` | function | `SecureMemory.py` |
| `disable_secure_memory` | function | `SecureMemory.py` |
| `enable_secure_memory` | function | `SecureMemory.py` |
| `secure_bytearray` | context manager | `SecureMemory.py` |
| `secure_bytes` | context manager (deprecated) | `SecureMemory.py` |
| `SecureBuffer` | class | `SecureMemory.py` |

---

## 3. `SecureChatCompletion` (entrypoint)

### Constructor

```python
SecureChatCompletion(
    base_url: str = "https://api.nomyo.ai",
    allow_http: bool = False,
    api_key: Optional[str] = None,
    secure_memory: bool = True,
    key_dir: Optional[str] = None,
    max_retries: int = 2
)
```

| Param | Default | Description |
|---|---|---|
| `base_url` | `"https://api.nomyo.ai"` | NOMYO Router base URL. HTTPS enforced unless `allow_http=True`. |
| `allow_http` | `False` | Permit `http://` URLs (dev only). |
| `api_key` | `None` | Bearer token for auth. Can also be passed per-call via `create()`. |
| `secure_memory` | `True` | Enable memory locking/zeroing. Warns if unavailable. |
| `key_dir` | `None` | Directory to persist RSA keys. `None` = ephemeral (in-memory only). |
| `max_retries` | `2` | Retries on 429/500/502/503/504 + network errors. Exponential backoff: 1s, 2s, 4s… |

### `create(model, messages, **kwargs) -> Dict[str, Any]`

Async method. Returns a **dict** (not an object). Same signature as `openai.ChatCompletion.create()`.

| Param | Type | Required | Description |
|---|---|---|---|
| `model` | `str` | yes | Model identifier, e.g. `"Qwen/Qwen3-0.6B"` |
| `messages` | `List[Dict]` | yes | OpenAI-format messages: `[{"role": "user", "content": "..."}]` |
| `temperature` | `float` | no | 0–2 |
| `max_tokens` | `int` | no | |
| `top_p` | `float` | no | |
| `stop` | `str \| List[str]` | no | |
| `presence_penalty` | `float` | no | -2.0 to 2.0 |
| `frequency_penalty` | `float` | no | -2.0 to 2.0 |
| `n` | `int` | no | Number of completions |
| `best_of` | `int` | no | |
| `seed` | `int` | no | |
| `logit_bias` | `Dict[str, float]` | no | |
| `user` | `str` | no | |
| `tools` | `List[Dict]` | no | Tool definitions passed through to llama.cpp |
| `tool_choice` | `str` | no | `"auto"`, `"none"`, or specific tool name |
| `response_format` | `Dict` | no | `{"type": "json_object"}` or `{"type": "json_schema", ...}` |
| `stream` | `bool` | no | **NOT supported.** Server rejects with HTTP 400. Always use `False`. |
| `base_url` | `str` | no | Per-call override (creates temp client internally). |
| `security_tier` | `str` | no | `"standard"`, `"high"`, or `"maximum"`. Invalid values raise `ValueError`. |
| `api_key` | `str` | no | Per-call override of instance `api_key`. |

**Return value:** `Dict[str, Any]` — OpenAI-compatible response dict (see §6.2).

### `acreate(model, messages, **kwargs) -> Dict[str, Any]`

Async alias for `create()`. Identical behavior.

---

## 4. `SecureCompletionClient` (low-level)

### Constructor

```python
SecureCompletionClient(
    router_url: str = "https://api.nomyo.ai",
    allow_http: bool = False,
    secure_memory: bool = True,
    max_retries: int = 2
)
```

Same semantics as `SecureChatCompletion` constructor (maps directly to inner client).

### Instance attributes

| Attribute | Type | Description |
|---|---|---|
| `router_url` | `str` | Base URL (trailing slash stripped). |
| `private_key` | `rsa.RSAPrivateKey \| None` | Loaded/generated RSA private key. |
| `public_key_pem` | `str \| None` | PEM-encoded public key string. |
| `key_size` | `int` | Always `4096`. |
| `allow_http` | `bool` | HTTP allowance flag. |
| `max_retries` | `int` | Retry count. |
| `_use_secure_memory` | `bool` | Whether secure memory ops are active. |

### `generate_keys(save_to_file: bool = False, key_dir: str = "client_keys", password: Optional[str] = None) -> None`

Generates a 4096-bit RSA key pair (public exponent `65537`). If `save_to_file=True`:
- Creates `key_dir/` (mode 755).
- Writes `private_key.pem` with mode `0o600`.
- Writes `public_key.pem` with mode `0o644`.
- If `password` is given, private key is encrypted with `BestAvailableEncryption`.

### `load_keys(private_key_path: str, public_key_path: Optional[str] = None, password: Optional[str] = None) -> None`

Loads an RSA private key from disk. If `public_key_path` is omitted, derives the public key from the loaded private key. Validates key size >= 2048 bits.

### `fetch_server_public_key() -> str` (async)

`GET {router_url}/pki/public_key`
- Returns server PEM public key as string.
- Validates it parses as a valid PEM public key.
- Raises `SecurityError` if URL is not HTTPS and `allow_http=False`.

### `encrypt_payload(payload: Dict[str, Any]) -> bytes` (async)

Encrypts a dict payload using hybrid encryption. Returns raw encrypted bytes (JSON package, serialized to bytes).

**Encryption process:**
1. Serialize payload to JSON → `bytearray`.
2. Validate size <= 10 MB.
3. Generate 256-bit AES key via `secrets.token_bytes(32)` → `bytearray`.
4. If secure memory enabled: lock both payload and AES key in memory.
5. Call `_do_encrypt()` (see below).
6. Zero/destroy payload and AES key from memory on exit.

### `_do_encrypt(payload_bytes: bytes \| bytearray, aes_key: bytes \| bytearray) -> bytes` (async)

Core hybrid encryption routine. **This is the wire format constructor.**

```
1. nonce = secrets.token_bytes(12)           # 96-bit GCM nonce
2. ciphertext = AES-256-GCM_encrypt(aes_key, nonce, payload_bytes)
3. tag = GCM_tag
4. server_pubkey = await fetch_server_public_key()
5. encrypted_aes_key = RSA-OAEP-SHA256_encrypt(server_pubkey, aes_key_bytes)
6. Build JSON package (see §6.1)
7. Return json.dumps(package).encode('utf-8')
```

### `decrypt_response(encrypted_response: bytes, payload_id: str) -> Dict[str, Any]` (async)

Decrypts a server response.

**Validation chain:**
1. Parse JSON.
2. Check `version == "1.0"` — raises `ValueError` if mismatch.
3. Check `algorithm == "hybrid-aes256-rsa4096"` — raises `ValueError` if mismatch.
4. Validate `encrypted_payload` has `ciphertext`, `nonce`, `tag`.
5. Require `self.private_key` is not `None`.
6. Decrypt AES key: `RSA-OAEP-SHA256_decrypt(private_key, encrypted_aes_key)`.
7. Decrypt payload: `AES-256-GCM_decrypt(aes_key, nonce, tag, ciphertext)`.
8. Parse decrypted bytes as JSON → response dict.
9. Attach `_metadata` if not present (see §6.2).

Any decryption failure (except JSON parse errors) raises `SecurityError("Decryption failed: integrity check or authentication failed")`.

### `send_secure_request(payload, payload_id, api_key=None, security_tier=None) -> Dict[str, Any]` (async)

Full request lifecycle: encrypt → HTTP POST → retry → decrypt → return.

**Request headers:**
```
Content-Type: application/octet-stream
X-Payload-ID: {payload_id}
X-Public-Key: {url_encoded_pem_public_key}
Authorization: Bearer {api_key}            (if api_key is provided)
X-Security-Tier: {tier}                    (if security_tier is provided)
```

**POST** to `{router_url}/v1/chat/secure_completion` with encrypted payload as body.

**Retry logic:**
- Retryable status codes: `{429, 500, 502, 503, 504}`.
- Backoff: `2^(attempt-1)` seconds (1s, 2s, 4s…).
- Total attempts: `max_retries + 1`.
- Network errors also retry.
- Non-retryable exceptions propagate immediately.

**Status → exception mapping:**

| Status | Exception |
|---|---|
| 200 | Return decrypted response dict |
| 400 | `InvalidRequestError` |
| 401 | `AuthenticationError` |
| 403 | `ForbiddenError` |
| 404 | `APIError` |
| 429 | `RateLimitError` |
| 500 | `ServerError` |
| 503 | `ServiceUnavailableError` |
| 502/504 | `APIError` (retryable) |
| other | `APIError` (non-retryable) |
| network error | `APIConnectionError` |

---

## 5. Encryption Wire Format

The encrypted package is a JSON object sent as `application/octet-stream`:

```json
{
  "version": "1.0",
  "algorithm": "hybrid-aes256-rsa4096",
  "encrypted_payload": {
    "ciphertext": "<base64>",
    "nonce": "<base64>",
    "tag": "<base64>"
  },
  "encrypted_aes_key": "<base64>",
  "key_algorithm": "RSA-OAEP-SHA256",
  "payload_algorithm": "AES-256-GCM"
}
```

| Field | Encoding | Description |
|---|---|---|
| `version` | string | Protocol version. **Never change** — used for downgrade detection. |
| `algorithm` | string | `"hybrid-aes256-rsa4096"`. **Never change** — used for downgrade detection. |
| `encrypted_payload.ciphertext` | base64 | AES-256-GCM encrypted payload. |
| `encrypted_payload.nonce` | base64 | 12-byte GCM nonce. |
| `encrypted_payload.tag` | base64 | 16-byte GCM authentication tag. |
| `encrypted_aes_key` | base64 | RSA-OAEP-SHA256 encrypted 32-byte AES key. |
| `key_algorithm` | string | `"RSA-OAEP-SHA256"` |
| `payload_algorithm` | string | `"AES-256-GCM"` |

---

## 6. Data Structures

### 6.1 Encrypted Request Payload (before encryption)

The dict passed to `encrypt_payload()` has this structure:

```json
{
  "model": "Qwen/Qwen3-0.6B",
  "messages": [
    {"role": "user", "content": "Hello"}
  ],
  "temperature": 0.7,
  "...": "any other OpenAI-compatible param"
}
```

**Important:** `api_key` is **never** included in the encrypted payload. It is sent only as the `Authorization: Bearer` HTTP header.

### 6.2 Response Dict (after decryption)

```json
{
  "id": "chatcmpl-123",
  "object": "chat.completion",
  "created": 1234567890,
  "model": "Qwen/Qwen3-0.6B",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "The capital of France is Paris.",
        "tool_calls": [...],
        "reasoning_content": "..."
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 10,
    "completion_tokens": 20,
    "total_tokens": 30
  },
  "_metadata": {
    "payload_id": "openai-compat-abc123",
    "processed_at": 1765250382,
    "is_encrypted": true,
    "encryption_algorithm": "hybrid-aes256-rsa4096",
    "security_tier": "standard",
    "memory_protection": {
      "platform": "linux",
      "memory_locking": true,
      "secure_zeroing": true,
      "core_dump_prevention": true
    },
    "cuda_device": {
      "available": true,
      "device_hash": "sha256_hex"
    }
  }
}
```

### 6.3 Security Tier Values

| Value | Hardware | Use case |
|---|---|---|
| `"standard"` | GPU | General secure inference |
| `"high"` | CPU/GPU | Sensitive business data |
| `"maximum"` | CPU only | PHI, classified data |

Sent as `X-Security-Tier` HTTP header. Invalid values raise `ValueError`.

---

## 7. Error Class Hierarchy

All errors are exceptions. `APIError` subclasses carry `status_code` and `error_details`.

```
Exception
└── APIError                     (base, has message/status_code/error_details)
    ├── AuthenticationError      (status_code=401)
    ├── InvalidRequestError      (status_code=400)
    ├── RateLimitError           (status_code=429)
    ├── ForbiddenError           (status_code=403)
    ├── ServerError              (status_code=500)
    └── ServiceUnavailableError  (status_code=503)

Exception
└── SecurityError                (crypto/key failure, no status_code)

Exception
└── APIConnectionError           (network failure, no status_code)
```

**APIError constructor:**
```python
APIError(message: str, status_code: Optional[int] = None, error_details: Optional[Dict] = None)
```

---

## 8. SecureMemory Module

Optional, platform-specific. Fails gracefully if unavailable (e.g. Windows on some Python builds).

### `SecureBuffer` class

Wraps a `bytearray` with memory locking and guaranteed zeroing on exit.

| Attribute/Method | Type | Description |
|---|---|---|
| `data` | `bytearray` | Underlying mutable buffer |
| `address` | `int` | Memory address (via ctypes) |
| `size` | `int` | Buffer size in bytes |
| `lock() -> bool` | method | Attempt memory lock |
| `unlock() -> bool` | method | Unlock memory |
| `zero()` | method | Securely zero contents |
| `__enter__` / `__exit__` | context mgr | Auto-lock on enter, auto-zero+unlock on exit |

### `secure_bytearray(data: bytes \| bytearray, lock: bool = True) -> SecureBuffer` (context manager)

Recommended secure handling. Converts input to `bytearray`, locks (best-effort), yields `SecureBuffer`. Always zeros on exit, even on exception.

### `secure_bytes(data: bytes, lock: bool = True) -> SecureBuffer` (context manager, **deprecated**)

Same as `secure_bytearray` but accepts immutable `bytes`. Emits deprecation warning. Original bytes cannot be zeroed.

### `get_memory_protection_info() -> Dict[str, Any]`

Returns protection capabilities:

```json
{
  "enabled": true,
  "platform": "linux",
  "protection_level": "full",
  "has_memory_locking": true,
  "has_secure_zeroing": true,
  "supports_full_protection": true,
  "page_size": 4096
}
```

`protection_level` values: `"full"`, `"zeroing_only"`, `"none"`.

### `disable_secure_memory()` / `enable_secure_memory()`

Globally disable/re-enable secure memory operations.

---

## 9. Constants

| Constant | Value | Location | Notes |
|---|---|---|---|
| Protocol version | `"1.0"` | `SecureCompletionClient.py` | **Never change** — downgrade detection |
| Algorithm string | `"hybrid-aes256-rsa4096"` | `SecureCompletionClient.py` | **Never change** — downgrade detection |
| RSA key size | `4096` | `SecureCompletionClient.py` | Fixed |
| RSA public exponent | `65537` | `SecureCompletionClient.py` | Fixed |
| AES key size | `32` bytes (256-bit) | `SecureCompletionClient.py` | Per-request ephemeral |
| GCM nonce size | `12` bytes (96-bit) | `SecureCompletionClient.py` | Per-request via `secrets.token_bytes` |
| Max payload size | `10 * 1024 * 1024` (10 MB) | `SecureCompletionClient.py` | DoS protection |
| Default max retries | `2` | Both client classes | Exponential backoff: 1s, 2s, 4s… |
| Private key file mode | `0o600` | `SecureCompletionClient.py` | Owner read/write only |
| Public key file mode | `0o644` | `SecureCompletionClient.py` | Owner rw, group/others r |
| Min RSA key size (validation) | `2048` | `SecureCompletionClient.py` | `_validate_rsa_key` |
| Valid security tiers | `["standard", "high", "maximum"]` | `SecureCompletionClient.py` | Case-sensitive |
| Retryable status codes | `{429, 500, 502, 503, 504}` | `SecureCompletionClient.py` | |
| Package version | `"0.2.7"` | `pyproject.toml` + `__init__.py` | Bump both |

---

## 10. Endpoint URLs

| Endpoint | Method | Purpose |
|---|---|---|
| `{router_url}/pki/public_key` | GET | Fetch server RSA public key |
| `{router_url}/v1/chat/secure_completion` | POST | Encrypted chat completion |

---

## 11. Key Lifecycle

1. **First `create()` call** → `_ensure_keys()` runs (async, double-checked locking via `asyncio.Lock`).
2. If `key_dir` is set:
   - Try `load_keys()` from `{key_dir}/private_key.pem` + `{key_dir}/public_key.pem`.
   - If that fails → `generate_keys(save_to_file=True, key_dir=key_dir)`.
3. If `key_dir` is `None` → `generate_keys()` (ephemeral, in-memory only).
4. Keys are reused across all subsequent calls until the client is discarded.

---

## 12. HTTP Client Details

- Uses `httpx.AsyncClient` with `timeout=60.0`.
- SSL verification enabled for HTTPS URLs; disabled for `http://`.
- Request body is raw bytes (not JSON) — `Content-Type: application/octet-stream`.
- Public key is URL-encoded in the `X-Public-Key` header.

---

## 13. Memory Protection Platform Matrix

| Platform | Locking | Zeroing |
|---|---|---|
| Linux | `mlock()` via `libc.so.6` | `memset()` via `libc.so.6` |
| Windows | `VirtualLock()` via `kernel32` | `RtlZeroMemory()` via `ntdll` + Python-level fallback |
| macOS | `mlock()` via `libc.dylib` | `memset()` via `libc.dylib` |
| Other | No lock | Python-level byte-by-byte zeroing |

mlock may fail with `EPERM` (need `CAP_IPC_LOCK` or `ulimit -l` increase) — degrades to zeroing-only gracefully.