AeroNyx Chat API 連携ガイド

from __future__ import annotations

import hashlib, json, os, time, uuid

import requests
from nacl.signing import SigningKey

from aeronyx_chat import open_, seal

BASE = "https://api.aeronyx.network"
PREFIX = "/api/relay/developer/v1"


def call(key: SigningKey, method: str, path: str, body: dict | None = None):
    """Signs and sends one request. `path` is the full path after the host."""
    raw = b"" if body is None else json.dumps(body, separators=(",", ":")).encode()
    seconds = str(int(time.time()))
    nonce = os.urandom(16)
    digest = hashlib.sha256(
        b"AeroNyx/DeveloperChatRequestV1\0" + method.encode() + b"\0"
        + path.encode() + b"\0" + seconds.encode() + b"\0"
        + nonce + hashlib.sha256(raw).digest()
    ).digest()
    signature = key.sign(digest).signature.hex()
    pub = key.verify_key.encode().hex()
    headers = {
        "Authorization": f"AeroNyx-Chat-V1 {pub}:{seconds}:{nonce.hex()}:{signature}",
        "Content-Type": "application/json",
    }
    # Send exactly the bytes that were signed.
    return requests.request(method, BASE + path, data=raw or None,
                            headers=headers, timeout=20)


alice, bob = SigningKey.generate(), SigningKey.generate()
bob_address = bob.verify_key.encode().hex()

# 1. Alice seals and sends a message to Bob.
message_id = uuid.uuid4()
now = int(time.time())
sent = call(alice, "POST", PREFIX + "/messages/", {
    "receiver_pubkey": bob_address,
    "message_id": str(message_id),
    "discriminant": 11,
    "sent_at": now,
    "payload_b64": seal(alice, bob.verify_key.encode(), "Hello Bob", message_id, now),
})
print("send:", sent.status_code, sent.json())

# 2. Bob fetches his inbox, decrypts, and then acknowledges.
inbox = call(bob, "GET", PREFIX + "/inbox/?limit=50").json()
for item in inbox["messages"]:
    opened = open_(bob, item["payload_b64"])
    print("received:", opened["plaintext"], "from", opened["sender"][:8])
    # Store the message durably here, then acknowledge it.
    ack = call(bob, "POST", PREFIX + "/acks/", {"message_ids": [item["msg_id"]]})
    print("ack:", ack.status_code, ack.json())

Authorization: AeroNyx-Chat-V1 <public-key-hex>:<unix-seconds>:<nonce-hex>:<signature-hex>

SHA256(
  "AeroNyx/DeveloperChatRequestV1\0" ||
  UPPERCASE_HTTP_METHOD || "\0" ||
  PATH_WITH_QUERY || "\0" ||
  ASCII_UNIX_SECONDS || "\0" ||
  NONCE_BYTES ||
  SHA256(EXACT_HTTP_BODY_BYTES)
)

{
  "seed_hex": "0303030303030303030303030303030303030303030303030303030303030303",
  "public_key_hex": "ed4928c628d1c2c6eae90338905995612959273a5c63f93636c14614ac8737d1",
  "method": "POST",
  "path_with_query": "/api/relay/developer/v1/messages/",
  "unix_seconds": "1780000000",
  "nonce_hex": "000102030405060708090a0b0c0d0e0f",
  "body": "{\"receiver_pubkey\":\"8139770ea87d175f56a35466c34c7ecccb8d8a91b4ee37a25df60f5b8fc9b394\",\"message_id\":\"018f5164-c1b2-7e2b-9d8a-2c60597f4c2f\",\"discriminant\":11,\"sent_at\":1780000000,\"payload_b64\":\"AAAA\"}",
  "body_sha256_hex": "1971a2ef86b2a085e033fd65313981c8668204d49cedbe530875036d1f45c9cc",
  "digest_hex": "6f4d0ca6dcd1221780b2dae45dd94e4bae7e79f266e8bb69f2d50c20de08b276",
  "signature_hex": "14ed2108e1ecf8ce5d04299e59af6d00dec218d62592de127e6a640f235ea4e9703004561fc08e929d0159f92fc51d35a881eec7d0eb16f19d94270c6262cb0c",
  "authorization": "AeroNyx-Chat-V1 ed4928c628d1c2c6eae90338905995612959273a5c63f93636c14614ac8737d1:1780000000:000102030405060708090a0b0c0d0e0f:14ed2108e1ecf8ce5d04299e59af6d00dec218d62592de127e6a640f235ea4e9703004561fc08e929d0159f92fc51d35a881eec7d0eb16f19d94270c6262cb0c"
}

{
  "receiver_pubkey": "<64 lowercase hex characters>",
  "message_id": "018f5164-c1b2-7e2b-9d8a-2c60597f4c2f",
  "discriminant": 11,
  "sent_at": 1780000000,
  "payload_b64": "<sealed envelope, Base64>"
}

{
  "message_id": "018f5164-c1b2-7e2b-9d8a-2c60597f4c2f",
  "accepted": true,
  "delivered_live": false
}

{
  "messages": [{
    "sender_pubkey": "<hex>",
    "discriminant": 11,
    "payload_b64": "<ciphertext>",
    "timestamp": 1780000000,
    "msg_id": "018f5164-c1b2-7e2b-9d8a-2c60597f4c2f"
  }],
  "has_more": false
}

{
  "message_ids": ["018f5164-c1b2-7e2b-9d8a-2c60597f4c2f"]
}

{"type": "relay_offline_ack", "msg_id": "018f5164-c1b2-7e2b-9d8a-2c60597f4c2f"}

my_x25519_secret = clamp(SHA-512(my_ed25519_seed)[0..32])
peer_x25519      = Edwards-to-Montgomery(peer_ed25519_public_key)
raw              = X25519(my_x25519_secret, peer_x25519)
key              = HKDF-SHA256(salt = empty, ikm = raw, info = "AERONYX-P2P-KEY", length = 32)

sender_pubkey   32 bytes
message_id      16 bytes   (the raw bytes of the UUID sent as message_id)
receiver_pubkey 32 bytes
timestamp        8 bytes   (u64, Unix seconds; use the same value as sent_at)
content_type     1 byte    (0 = text)
SHA-256(ciphertext) 32 bytes

message_id      16 bytes
sender_pubkey   32 bytes
receiver_pubkey 32 bytes
timestamp        8 bytes   (u64)
ciphertext_len   8 bytes   (u64)
ciphertext       ciphertext_len bytes
nonce           24 bytes
content_type     4 bytes   (u32, 0 = text)
signature       64 bytes

"""AeroNyx 1:1 chat envelope (discriminant 11). Requires PyNaCl."""

from __future__ import annotations

import base64
import hashlib
import hmac
import os
import struct
import uuid

from nacl.bindings import (
    crypto_aead_xchacha20poly1305_ietf_decrypt,
    crypto_aead_xchacha20poly1305_ietf_encrypt,
    crypto_scalarmult,
    crypto_sign_ed25519_pk_to_curve25519,
    crypto_sign_ed25519_sk_to_curve25519,
)
from nacl.signing import SigningKey, VerifyKey

CONTENT_TEXT = 0
_HKDF_INFO = b"AERONYX-P2P-KEY"


def _hkdf_sha256(ikm: bytes, info: bytes, length: int = 32) -> bytes:
    # RFC 5869 with an empty salt (= 32 zero bytes).
    prk = hmac.new(b"\x00" * 32, ikm, hashlib.sha256).digest()
    okm, block, counter = b"", b"", 1
    while len(okm) < length:
        block = hmac.new(prk, block + info + bytes([counter]), hashlib.sha256).digest()
        okm += block
        counter += 1
    return okm[:length]


def chat_key(my_key: SigningKey, peer_public: bytes, hkdf: bool = True) -> bytes:
    """X25519 over the Ed25519 identities, then HKDF-SHA256."""
    my_secret = bytes(my_key) + my_key.verify_key.encode()  # libsodium 64-byte sk
    raw = crypto_scalarmult(
        crypto_sign_ed25519_sk_to_curve25519(my_secret),
        crypto_sign_ed25519_pk_to_curve25519(peer_public),
    )
    return _hkdf_sha256(raw, _HKDF_INFO) if hkdf else raw


def _sign_data(sender, message_id, receiver, timestamp, content_type, ciphertext):
    return (
        sender
        + message_id
        + receiver
        + struct.pack("<Q", timestamp)
        + bytes([content_type])  # one byte here ...
        + hashlib.sha256(ciphertext).digest()
    )


def seal(my_key: SigningKey, receiver: bytes, text: str, message_id: uuid.UUID,
         timestamp: int, nonce: bytes | None = None) -> str:
    """Returns payload_b64 for POST /messages/ (discriminant 11)."""
    nonce = nonce if nonce is not None else os.urandom(24)
    key = chat_key(my_key, receiver)
    ciphertext = crypto_aead_xchacha20poly1305_ietf_encrypt(
        text.encode("utf-8"), None, nonce, key)  # ciphertext || 16-byte tag, no AAD
    sender = my_key.verify_key.encode()
    mid = message_id.bytes
    signature = my_key.sign(
        _sign_data(sender, mid, receiver, timestamp, CONTENT_TEXT, ciphertext)
    ).signature
    envelope = (
        mid
        + sender
        + receiver
        + struct.pack("<Q", timestamp)
        + struct.pack("<Q", len(ciphertext))
        + ciphertext
        + nonce
        + struct.pack("<I", CONTENT_TEXT)  # ... four bytes here
        + signature
    )
    return base64.b64encode(envelope).decode("ascii")


def open_(my_key: SigningKey, payload_b64: str) -> dict:
    """Verifies and decrypts an inbox payload addressed to my_key."""
    env = base64.b64decode(payload_b64, validate=True)
    if len(env) < 16 + 32 + 32 + 8 + 8 + 16 + 24 + 4 + 64:
        raise ValueError("envelope too short")
    mid, sender, receiver = env[0:16], env[16:48], env[48:80]
    timestamp, ct_len = struct.unpack("<QQ", env[80:96])
    if len(env) != 96 + ct_len + 24 + 4 + 64:
        raise ValueError("envelope length mismatch")
    ciphertext = env[96:96 + ct_len]
    nonce = env[96 + ct_len:120 + ct_len]
    (content_type,) = struct.unpack("<I", env[120 + ct_len:124 + ct_len])
    signature = env[124 + ct_len:]
    if receiver != my_key.verify_key.encode():
        raise ValueError("envelope is addressed to another identity")
    VerifyKey(sender).verify(
        _sign_data(sender, mid, receiver, timestamp, content_type, ciphertext), signature)
    # Current App versions use the HKDF key; very old ones sent with the raw key.
    for hkdf in (True, False):
        try:
            plaintext = crypto_aead_xchacha20poly1305_ietf_decrypt(
                ciphertext, None, nonce, chat_key(my_key, sender, hkdf))
            break
        except Exception:  # noqa: BLE001 - try the legacy key next
            plaintext = None
    if plaintext is None:
        raise ValueError("decryption failed")
    return {
        "message_id": str(uuid.UUID(bytes=mid)),
        "sender": sender.hex(),
        "timestamp": timestamp,
        "content_type": content_type,
        "plaintext": plaintext.decode("utf-8"),
    }

{
  "sender_seed_hex": "0101010101010101010101010101010101010101010101010101010101010101",
  "sender_pubkey": "8a88e3dd7409f195fd52db2d3cba5d72ca6709bf1d94121bf3748801b40f6f5c",
  "receiver_seed_hex": "0202020202020202020202020202020202020202020202020202020202020202",
  "receiver_pubkey": "8139770ea87d175f56a35466c34c7ecccb8d8a91b4ee37a25df60f5b8fc9b394",
  "message_id": "018f5164-c1b2-7e2b-9d8a-2c60597f4c2f",
  "timestamp": 1780000000,
  "nonce_hex": "000102030405060708090a0b0c0d0e0f1011121314151617",
  "plaintext": "Hello from AeroNyx",
  "shared_key_hex": "dd08f8bb45a43c9bc186fdaf436d47e8e05b0aca44fa2bb9473769da0407652f",
  "payload_b64": "AY9RZMGyfiudiixgWX9ML4qI4910CfGV/VLbLTy6XXLKZwm/HZQSG/N0iAG0D29cgTl3Dqh9F19Wo1Rmw0x+zMuNipG07jeiXfYPW4/Js5QApRhqAAAAACIAAAAAAAAA1vVyzdTx1kAdPEI7AGO12ppwLwaME0K9PJKd+u7OgWq0rwABAgMEBQYHCAkKCwwNDg8QERITFBUWFwAAAACAlpInhB5A9cD4LqKAT0OE0OpbMqT5w/xB8IiHrzuyg9LPjF9gDHdOekPNoHNxDMeu3Ift0UB69OGSofdfwKIN"
}