refactor: use pynostr/coincurve instead of secp256k1 (#18)

---------

Co-authored-by: Riccardo Balbo <os@rblb.it>
Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

.devcontainer/setup.sh

@@ -10,7 +10,7 @@ if [ ! -d ./lnbits ] ; then
 fi
 cd lnbits
 echo $PWD
-git checkout v1.0.0-rc7
+git checkout dev
 poetry env use 3.12
 POETRY_PYTHON_PATH=$(poetry env info -p)/bin/python
 ln -sf $POETRY_PYTHON_PATH /home/vscode/python

migrations.py

@@ -1,4 +1,4 @@
-import secp256k1
+from coincurve import PrivateKey
 
 
 async def m001_initial(db):
@@ -72,14 +72,14 @@ async def m003_default_config(db):
         ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value;
         """
     )
-    new_private_key = bytes.hex(secp256k1._gen_private_key())
+    private_key = PrivateKey()
     await db.execute(
         """
         INSERT INTO nwcprovider.config (key, value)
         VALUES ('provider_key', :provider_key)
         ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value;
         """,
-        {"provider_key": new_private_key},
+        {"provider_key": private_key.to_hex()},
     )
 
 

nwcp.py

@@ -1,5 +1,4 @@
 import asyncio
-import base64
 import hashlib
 import json
 import random
@@ -7,13 +6,11 @@ import time
 from collections.abc import Awaitable, Callable
 from typing import Any, Union
 
-import secp256k1
+from coincurve import PublicKeyXOnly
-from Cryptodome import Random
-from Cryptodome.Cipher import AES
-from Cryptodome.Util.Padding import pad, unpad
 from lnbits.helpers import encrypt_internal_message
 from lnbits.settings import settings
 from loguru import logger
+from pynostr.key import PrivateKey
 from websockets.legacy.client import connect
 
 
@@ -75,7 +72,7 @@ class MainSubscription:
 class NWCServiceProvider:
     def __init__(
         self,
-        private_key: str | None = None,
+        private_key_hex: str | None = None,
         relay: str | None = None,
         handle_missed_events: int = 0,
     ):
@@ -90,15 +87,18 @@ class NWCServiceProvider:
             )
         self.relay = relay
 
-        if not private_key:  # Create random key
+        if not private_key_hex:  # Create random key
-            private_key = bytes.hex(secp256k1._gen_private_key())
+            self.private_key = PrivateKey()
+            self.private_key_hex = self.private_key.hex()
+        else:
+            self.private_key = PrivateKey.from_hex(private_key_hex)
+            self.private_key_hex = private_key_hex
 
-        self.private_key = secp256k1.PrivateKey(bytes.fromhex(private_key))
+        self.public_key = self.private_key.public_key
-        self.private_key_hex = private_key
-        self.public_key = self.private_key.pubkey
         if not self.public_key:
             raise Exception("Invalid public key")
-        self.public_key_hex = self.public_key.serialize().hex()[2:]
+
+        self.public_key_hex = self.public_key.hex()
 
         # List of supported methods
         self.supported_methods: list[str] = []
@@ -314,7 +314,7 @@ class NWCServiceProvider:
         nwc_pubkey = event["pubkey"]
         content = event["content"]
         # Decrypt the content
-        content = self._decrypt_content(content, nwc_pubkey)
+        content = self.private_key.decrypt_message(content, nwc_pubkey)
         # Deserialize content
         content = json.loads(content)
         # Handle request
@@ -364,7 +364,9 @@ class NWCServiceProvider:
             # Reference user
             res["tags"].append(["p", nwc_pubkey])
             # Finalize response event
-            res["content"] = self._encrypt_content(res["content"], nwc_pubkey)
+            res["content"] = self.private_key.encrypt_message(
+                res["content"], nwc_pubkey
+            )
             self._sign_event(res)
 
             # Register response for this request, so we knows it is not stale
@@ -513,65 +515,6 @@ class NWCServiceProvider:
                 logger.debug("Reconnecting to NWC relay...")
                 await self._ratelimit("connecting")
 
-    def _encrypt_content(
-        self, content: str, pubkey_hex: str, iv_seed: int | None = None
-    ) -> str:
-        """
-        Encrypts the content for the given public key
-
-        Args:
-            content (str): The content to be encrypted.
-            pubkey_hex (str): The public key in hex format.
-
-        Returns:
-            str: The encrypted content.
-        """
-        pubkey = secp256k1.PublicKey(bytes.fromhex("02" + pubkey_hex), True)
-        shared = pubkey.tweak_mul(bytes.fromhex(self.private_key_hex)).serialize()[1:]
-        # random iv (16B)
-        if not iv_seed:
-            iv = Random.new().read(AES.block_size)
-        else:
-            iv = hashlib.sha256(iv_seed.to_bytes(32, byteorder="big")).digest()
-            iv = iv[: AES.block_size]
-
-        aes = AES.new(shared, AES.MODE_CBC, iv)
-
-        content_bytes = content.encode("utf-8")
-
-        # padding
-        content_bytes = pad(content_bytes, AES.block_size)
-
-        encrypted_b64 = base64.b64encode(aes.encrypt(content_bytes)).decode("ascii")
-        iv_b64 = base64.b64encode(iv).decode("ascii")
-        encrypted_content = encrypted_b64 + "?iv=" + iv_b64
-        return encrypted_content
-
-    def _decrypt_content(self, content: str, pubkey_hex: str) -> str:
-        """
-        Decrypts the content for the given public key
-
-        Args:
-            content (str): The encrypted content.
-            pubkey_hex (str): The public key in hex format.
-
-        Returns:
-            str: The decrypted content.
-        """
-        pubkey = secp256k1.PublicKey(bytes.fromhex("02" + pubkey_hex), True)
-
-        shared = pubkey.tweak_mul(bytes.fromhex(self.private_key_hex)).serialize()[1:]
-        # extract iv and content
-        (encrypted_content_b64, iv_b64) = content.split("?iv=")
-        encrypted_content = base64.b64decode(encrypted_content_b64.encode("ascii"))
-        iv = base64.b64decode(iv_b64.encode("ascii"))
-        # Decrypt
-        aes = AES.new(shared, AES.MODE_CBC, iv)
-        decrypted_bytes = aes.decrypt(encrypted_content)
-        decrypted_bytes = unpad(decrypted_bytes, AES.block_size)
-        decrypted = decrypted_bytes.decode("utf-8")
-        return decrypted
-
     def _verify_event(self, event: dict) -> bool:
         """
         Verify the event signature
@@ -596,10 +539,8 @@ class NWCServiceProvider:
         if event_id != event["id"]:  # Invalid event id
             return False
         pubkey_hex = event["pubkey"]
-        pubkey = secp256k1.PublicKey(bytes.fromhex("02" + pubkey_hex), True)
+        pubkey = PublicKeyXOnly(bytes.fromhex(pubkey_hex))
-        if not pubkey.schnorr_verify(
+        if not pubkey.verify(bytes.fromhex(event["sig"]), bytes.fromhex(event_id)):
-            bytes.fromhex(event_id), bytes.fromhex(event["sig"]), None, raw=True
-        ):
             return False
         return True
 
@@ -628,10 +569,8 @@ class NWCServiceProvider:
         event["id"] = event_id
         event["pubkey"] = self.public_key_hex
 
-        signature = (
+        signature = self.private_key.sign(bytes.fromhex(event_id))
-            self.private_key.schnorr_sign(bytes.fromhex(event_id), None, raw=True)
+        event["sig"] = signature.hex()  # type: ignore
-        ).hex()
-        event["sig"] = signature
         return event
 
     async def cleanup(self):

pyproject.toml

@@ -7,11 +7,8 @@ authors = [{ name = "Riccardo Balbo", email = "oc@rblb.it" }]
 urls = { Homepage = "https://lnbits.com", Repository = "https://github.com/lnbits/nwcprovider" }
 dependencies = [ "lnbits>1" ]
 
-[tool.poetry]
+[dependency-groups]
-package-mode = false
+dev = [
-
-[tool.uv]
-dev-dependencies = [
     "black",
     "pytest-asyncio",
     "pytest",
@@ -21,12 +18,15 @@ dev-dependencies = [
     "pytest-md",
 ]
 
+[tool.poetry]
+package-mode = false
+
 [tool.mypy]
 plugins = ["pydantic.mypy"]
 
 [[tool.mypy.overrides]]
 module = [
-  "secp256k1.*",
+  "pynostr.*",
 ]
 ignore_missing_imports = "True"
 

tests/integration/start.sh

@@ -19,8 +19,8 @@ fi
 docker run --name=lnbits_nwcprovider_ext_nostr_test \
 -d \
 --rm \
--v $PWD/strfry.conf:/etc/strfry.conf \
+-v $PWD/strfry.conf:/etc/strfry.conf:Z \
--v $PWD/strfry-data:/app/strfry-db \
+-v $PWD/strfry-data:/app/strfry-db:Z \
 -p 7777:7777 \
 ghcr.io/hoytech/strfry:latest
 

tests/integration/strfry.conf

@@ -47,7 +47,7 @@ relay {
     port = 7777
 
     # Set OS-limit on maximum number of open files/sockets (if 0, don't attempt to set) (restart required)
-    nofiles = 1000000
+    nofiles = 0
 
     # HTTP header that contains the client's real IP, before reverse proxying (ie x-real-ip) (MUST be all lower-case)
     realIpHeader = ""

tests/integration/test_all.py

@@ -1,5 +1,4 @@
 import asyncio
-import base64
 import hashlib
 import json
 import random
@@ -9,11 +8,8 @@ from typing import Union
 import bolt11
 import httpx
 import pytest
-import secp256k1
-from Cryptodome import Random
-from Cryptodome.Cipher import AES
-from Cryptodome.Util.Padding import pad, unpad
 from loguru import logger
+from pynostr.key import PrivateKey
 from websockets.legacy.client import connect
 
 wallets = {
@@ -95,12 +91,12 @@ async def refresh_wallet_balances():
 
 
 def gen_keypair():
-    private_key_hex = bytes.hex(secp256k1._gen_private_key())
+    private_key = PrivateKey()
-    private_key = secp256k1.PrivateKey(bytes.fromhex(private_key_hex))
+    private_key_hex = private_key.hex()
-    public_key = private_key.pubkey
+    public_key = private_key.public_key
     if not public_key:
         raise Exception("Error generating pubkey")
-    public_key_hex = public_key.serialize().hex()[2:]
+    public_key_hex = public_key.hex()
     return {"priv": private_key_hex, "pub": public_key_hex}
 
 
@@ -164,12 +160,12 @@ class NWCWallet:
         self.event_queue = []
         self.subscriptions_count = 0
         self.sub_id = ""
-        self.private_key = secp256k1.PrivateKey(bytes.fromhex(self.secret))
+        self.private_key = PrivateKey.from_hex(self.secret)
         self.private_key_hex = self.secret
-        self.public_key = self.private_key.pubkey
+        self.public_key = self.private_key.public_key
         if not self.public_key:
             raise Exception("Error generating pubkey")
-        self.public_key_hex = self.public_key.serialize().hex()[2:]
+        self.public_key_hex = self.public_key.hex()
         self.task = None
 
     async def close(self):
@@ -243,43 +239,13 @@ class NWCWallet:
             else:
                 break
 
-    def _encrypt_content(
-        self, content: str, pubkey_hex: str, iv_seed: int | None = None
-    ) -> str:
-        pubkey = secp256k1.PublicKey(bytes.fromhex("02" + pubkey_hex), True)
-        shared = pubkey.tweak_mul(bytes.fromhex(self.private_key_hex)).serialize()[1:]
-        if not iv_seed:
-            iv = Random.new().read(AES.block_size)
-        else:
-            iv = hashlib.sha256(iv_seed.to_bytes(32, byteorder="big")).digest()
-            iv = iv[: AES.block_size]
-        aes = AES.new(shared, AES.MODE_CBC, iv)
-        content_bytes = content.encode("utf-8")
-        content_bytes = pad(content_bytes, AES.block_size)
-        encrypted_b64 = base64.b64encode(aes.encrypt(content_bytes)).decode("ascii")
-        iv_b64 = base64.b64encode(iv).decode("ascii")
-        encrypted_content = encrypted_b64 + "?iv=" + iv_b64
-        return encrypted_content
-
-    def _decrypt_content(self, content: str, pubkey_hex: str) -> str:
-        pubkey = secp256k1.PublicKey(bytes.fromhex("02" + pubkey_hex), True)
-        shared = pubkey.tweak_mul(bytes.fromhex(self.private_key_hex)).serialize()[1:]
-        (encrypted_content_b64, iv_b64) = content.split("?iv=")
-        encrypted_content = base64.b64decode(encrypted_content_b64.encode("ascii"))
-        iv = base64.b64decode(iv_b64.encode("ascii"))
-        aes = AES.new(shared, AES.MODE_CBC, iv)
-        decrypted_bytes = aes.decrypt(encrypted_content)
-        decrypted_bytes = unpad(decrypted_bytes, AES.block_size)
-        decrypted = decrypted_bytes.decode("utf-8")
-        return decrypted
-
     async def _on_message(self, _, message: str):
         logger.debug("Received message: " + message)
         msg = json.loads(message)
         if msg[0] == "EVENT":  # Event message
             event = msg[2]
             nwc_pubkey = event["pubkey"]
-            content = self._decrypt_content(event["content"], nwc_pubkey)
+            content = self.private_key.decrypt_message(event["content"], nwc_pubkey)
             content = json.loads(content)
             self.event_queue.append(
                 {
@@ -312,10 +278,9 @@ class NWCWallet:
         event_id = hashlib.sha256(signature_data.encode()).hexdigest()
         event["id"] = event_id
         event["pubkey"] = self.public_key_hex
-        signature = (
+        signature = self.private_key.sign(bytes.fromhex(event_id))
-            self.private_key.schnorr_sign(bytes.fromhex(event_id), None, raw=True)
+        # type error? returns str but is bytes
-        ).hex()
+        event["sig"] = signature.hex()  # type: ignore
-        event["sig"] = signature
         return event
 
     async def send_event(self, method, params):
@@ -331,7 +296,7 @@ class NWCWallet:
             "content": json.dumps({"method": method, "params": params}),
         }
         logger.debug("Sending event: " + str(event))
-        event["content"] = self._encrypt_content(
+        event["content"] = self.private_key.encrypt_message(
             event["content"], self.provider_pub_hex
         )
         self._sign_event(event)
@@ -888,7 +853,7 @@ async def test_idor_vulnerability():
             f"http://localhost:5002/nwcprovider/api/v1/nwc/{nwc_wallet1['pubkey']}",
             headers={"X-Api-Key": wallets["wallet2"]["admin_key"]},
         )
-        assert resp.status_code == 500
+        assert resp.status_code == 400
         assert "Pubkey has no associated wallet" in resp.text
 
 

tests/unit/test_nwcp.py

@@ -33,25 +33,22 @@ def test_supported_methods(nwc_service_provider):
 
 def test_encrytdecrypt(nwc_service_provider, nwc_service_provider2):
     content = "Hello World"
-    expected_enc = "qVurNVISSl/9CfREIhk5Lg==?iv=QpCo5dI9gUcoLsSMLA7o7Q=="
+    enc_a = nwc_service_provider.private_key.encrypt_message(
-    enc_a = nwc_service_provider._encrypt_content(
+        content, nwc_service_provider2.public_key_hex
-        content, nwc_service_provider2.public_key_hex, 21
     )
-    enc_b = nwc_service_provider2._encrypt_content(
+    enc_b = nwc_service_provider2.private_key.encrypt_message(
-        content, nwc_service_provider.public_key_hex, 21
+        content, nwc_service_provider.public_key_hex
     )
 
-    dec_a = nwc_service_provider2._decrypt_content(
+    dec_a = nwc_service_provider2.private_key.decrypt_message(
         enc_a, nwc_service_provider.public_key_hex
     )
-    dec_b = nwc_service_provider._decrypt_content(
+    dec_b = nwc_service_provider.private_key.decrypt_message(
         enc_b, nwc_service_provider2.public_key_hex
     )
 
     assert dec_a == content
     assert dec_b == content
-    assert enc_a == expected_enc
-    assert enc_b == expected_enc
 
 
 def test_signverify(nwc_service_provider, nwc_service_provider2):
@@ -82,8 +79,8 @@ async def test_handle(nwc_service_provider, nwc_service_provider2):
     content = nwc_service_provider._json_dumps(
         {"method": "pay_invoice", "params": {"invoice": "abc"}}
     )
-    content = nwc_service_provider._encrypt_content(
+    content = nwc_service_provider.private_key.encrypt_message(
-        content, nwc_service_provider2.public_key_hex, 21
+        content, nwc_service_provider2.public_key_hex
     )
     event = {
         "kind": 23194,
@@ -108,7 +105,7 @@ async def test_handle(nwc_service_provider, nwc_service_provider2):
     assert len(sent_events) == 1
     for revent in sent_events:
         assert nwc_service_provider2._verify_event(revent)
-        content = nwc_service_provider2._decrypt_content(
+        content = nwc_service_provider2.private_key.decrypt_message(
             revent["content"], nwc_service_provider.public_key_hex
         )
         logger.debug(event)

views_api.py

@@ -1,10 +1,10 @@
 from http import HTTPStatus
 
-import secp256k1
 from fastapi import APIRouter, Depends, Request
 from fastapi.responses import JSONResponse
 from lnbits.core.models import WalletTypeInfo
 from lnbits.decorators import check_admin, require_admin_key
+from pynostr.key import PrivateKey
 
 from .crud import (
     create_nwc,
@@ -88,11 +88,13 @@ async def api_get_nwc(
     nwc = await get_nwc(
         GetNWC(pubkey=pubkey, wallet=wallet_id, include_expired=include_expired)
     )
+
     if not nwc:
-        raise Exception("Pubkey has no associated wallet")
+        raise ValueError("Pubkey has no associated wallet")
     res = NWCGetResponse(
         data=nwc, budgets=await get_budgets_nwc(GetBudgetsNWC(pubkey=pubkey))
     )
+
     return res
 
 
@@ -123,11 +125,11 @@ async def api_get_pairing_url(req: Request, secret: str) -> str:
                 scheme = "wss"
             netloc += "/nostrclient/api/v1/relay"
             relay = f"{scheme}://{netloc}"
-    psk = secp256k1.PrivateKey(bytes.fromhex(pprivkey))
+    psk = PrivateKey.from_hex(pprivkey)
-    ppk = psk.pubkey
+    ppk = psk.public_key
     if not ppk:
         raise Exception("Error generating pubkey")
-    ppubkey = ppk.serialize().hex()[2:]
+    ppubkey = ppk.hex()
     url = "nostr+walletconnect://"
     url += ppubkey
     url += "?relay=" + relay