From bef8df8d36d7e1e3e4375e760399b52475de14a0 Mon Sep 17 00:00:00 2001
From: Sergi Delgado Segura <sergi.delgado.s@gmail.com>
Date: Tue, 5 May 2020 18:46:37 +0200
Subject: [PATCH] plugin - fixes key generation

Key generation was performed using pyca/crpytography but keys were expected to be objects from coincurve. This comes from teos_cli where keys are generated beforehand and stored, and later on loaded from disk. The plugin generates keys and uses them straightaway (at least the first time), so it would fail in that case.
---
 watchtower-plugin/keys.py | 34 +++++++++++-----------------------
 1 file changed, 11 insertions(+), 23 deletions(-)

diff --git a/watchtower-plugin/keys.py b/watchtower-plugin/keys.py
index b42f98d..e7673f2 100644
--- a/watchtower-plugin/keys.py
+++ b/watchtower-plugin/keys.py
@@ -1,9 +1,6 @@
 import os.path
 from pathlib import Path
-from binascii import hexlify
-from cryptography.hazmat.backends import default_backend
-from cryptography.hazmat.primitives import serialization
-from cryptography.hazmat.primitives.asymmetric import ec
+from coincurve import PrivateKey
 
 from common.exceptions import InvalidKey
 from common.cryptographer import Cryptographer
@@ -11,21 +8,15 @@ from common.cryptographer import Cryptographer
 
 def save_key(sk, filename):
     """
-    Saves secret key on disk.
+    Saves the secret key on disk.
 
     Args:
-        sk (:obj:`PrivateKey`): a private key file to be saved on disk.
+        sk (:obj:`EllipticCurvePrivateKey`): a private key file to be saved on disk.
         filename (:obj:`str`): the name that will be given to the key file.
     """
 
-    der = sk.private_bytes(
-        encoding=serialization.Encoding.DER,
-        format=serialization.PrivateFormat.PKCS8,
-        encryption_algorithm=serialization.NoEncryption(),
-    )
-
     with open(filename, "wb") as der_out:
-        der_out.write(der)
+        der_out.write(sk.to_der())
 
 
 def generate_keys(data_dir):
@@ -36,8 +27,8 @@ def generate_keys(data_dir):
         data_dir (:obj:`str`): path to data directory where the keys will be stored.
 
     Returns:
-        :obj:`tuple`: a tuple containing a ``PrivateKey`` and a ``str`` representing the client sk and compressed
-        pk respectively.
+        :obj:`tuple`: a tuple containing a ``PrivateKey`` and a ``str`` representing the client sk and
+        compressed pk respectively.
 
     Raises:
         :obj:`FileExistsError`: if the key pair already exists in the given directory.
@@ -50,14 +41,11 @@ def generate_keys(data_dir):
     if os.path.exists(sk_file_name):
         raise FileExistsError("The client key pair already exists")
 
-    sk = ec.generate_private_key(ec.SECP256K1, default_backend())
+    sk = PrivateKey()
+    pk = sk.public_key
     save_key(sk, sk_file_name)
 
-    compressed_pk = sk.public_key().public_bytes(
-        encoding=serialization.Encoding.X962, format=serialization.PublicFormat.CompressedPoint
-    )
-
-    return sk, hexlify(compressed_pk).decode("utf-8")
+    return sk, Cryptographer.get_compressed_pk(pk)
 
 
 def load_keys(data_dir):
@@ -68,8 +56,8 @@ def load_keys(data_dir):
         data_dir (:obj:`str`): path to data directory where the keys are stored.
 
     Returns:
-        :obj:`tuple`: a tuple containing a ``PrivateKey`` and a ``str`` representing the client sk and compressed
-        pk respectively.
+        :obj:`tuple`: a tuple containing a ``EllipticCurvePrivateKey`` and a ``str`` representing the client sk and
+        compressed pk respectively.
 
     Raises:
         :obj:`InvalidKey <cli.exceptions.InvalidKey>`: if any of the keys is invalid or cannot be loaded.