From c11e9c77f8b8e60112968c1ef20e066f1437329b Mon Sep 17 00:00:00 2001
From: jMyles <justin@justinholmes.com>
Date: Fri, 9 Feb 2018 02:30:44 -0800
Subject: [PATCH 1/2] New ECDSA sign function.

---
 nkms/crypto/api.py | 53 ++++++++++++----------------------------------
 1 file changed, 13 insertions(+), 40 deletions(-)

diff --git a/nkms/crypto/api.py b/nkms/crypto/api.py
index 112c94e5c..379e046d1 100644
--- a/nkms/crypto/api.py
+++ b/nkms/crypto/api.py
@@ -1,10 +1,13 @@
-from typing import Tuple, Union, List
+from random import SystemRandom
+from typing import Tuple, Union
 
 import sha3
-from py_ecc.secp256k1 import N, privtopub, ecdsa_raw_recover, ecdsa_raw_sign
-from random import SystemRandom
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric import ec
+from py_ecc.secp256k1 import ecdsa_raw_recover
 
-from nkms.keystore.constants import SIG_KEYPAIR_BYTE, PUB_KEY_BYTE
+import umbral
+from nkms.crypto.signature import Signature
 
 SYSTEM_RAND = SystemRandom()
 
@@ -91,34 +94,6 @@ def ecdsa_bytes2pub(
     return (x, y)
 
 
-def ecdsa_gen_priv() -> bytes:
-    """
-    Generates an ECDSA Private Key.
-
-    :return: Byte encoded ECDSA privkey
-    """
-    privkey = secure_random_range(1, N)
-    return privkey.to_bytes(32, byteorder='big')  # TODO: Add metabytes.
-
-
-def ecdsa_priv2pub(
-        privkey: bytes,
-        to_bytes: bool = True
-) -> Union[bytes, Tuple[int]]:
-    """
-    Returns the public component of an ECDSA private key.
-
-    :param privkey: Private key as an int or bytestring
-    :param to_bytes: Serialize to bytes or not?
-
-    :return: Byte encoded or Tuple[int] ECDSA pubkey
-    """
-    pubkey = privtopub(privkey)
-    if to_bytes:
-        return SIG_KEYPAIR_BYTE + PUB_KEY_BYTE + ecdsa_pub2bytes(pubkey)
-    return pubkey
-
-
 def ecdsa_gen_sig(
         v: int,
         r: int,
@@ -155,20 +130,18 @@ def ecdsa_load_sig(
     return (v, r, s)
 
 
-def ecdsa_sign(
-        msghash: bytes,
-        privkey: bytes
-) -> Tuple[int, int, int]:
+def ecdsa_sign(message: bytes, privkey: umbral.keys.UmbralPrivateKey) -> bytes:
     """
     Accepts a hashed message and signs it with the private key given.
 
-    :param msghash: Hashed message to sign
+    :param message: Message to hash and sign
     :param privkey: Private key to sign with
 
-    :return: Tuple(v, r, s)
+    :return: signature
     """
-    v, r, s = ecdsa_raw_sign(msghash, privkey)
-    return (v, r, s)
+    cryptography_priv_key = privkey.bn_key.to_cryptography_priv_key()
+    signature_bytes = cryptography_priv_key.sign(message, ec.ECDSA(hashes.BLAKE2b(64)))
+    return Signature(signature_bytes)
 
 
 def ecdsa_verify(

From fd8ba6670d313b5cc33ddd90074817dbfbcc3fb7 Mon Sep 17 00:00:00 2001
From: jMyles <justin@justinholmes.com>
Date: Fri, 9 Feb 2018 02:33:38 -0800
Subject: [PATCH 2/2] SigningKeypair implements new ECDSA sign function.

---
 nkms/keystore/keypairs.py | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/nkms/keystore/keypairs.py b/nkms/keystore/keypairs.py
index fc7f2772d..04ad5a5a9 100644
--- a/nkms/keystore/keypairs.py
+++ b/nkms/keystore/keypairs.py
@@ -4,8 +4,7 @@ from nacl.secret import SecretBox
 
 from nkms.crypto import api as API
 from nkms.keystore import constants
-from npre import umbral
-from npre import elliptic_curve as ec
+import umbral
 
 
 class Keypair(object):
@@ -164,14 +163,15 @@ class SigningKeypair(Keypair):
 
         :param create_pubkey: Create the pubkey or not?
         """
-        self.privkey = API.ecdsa_gen_priv()
+        self.privkey = umbral.keys.UmbralPrivateKey.gen_key()
+
         if create_pubkey:
-            self._gen_pubkey()
+            self.pubkey = self.privkey.get_pub_key()
 
     def _gen_pubkey(self):
         self.pubkey = PublicKey(API.ecdsa_priv2pub(self.privkey))
 
-    def sign(self, msghash: bytes) -> bytes:
+    def sign(self, message: bytes) -> bytes:
         """
         Signs a hashed message and returns a signature.
 
@@ -179,8 +179,8 @@ class SigningKeypair(Keypair):
 
         :return: Signature in bytes
         """
-        v, r, s = API.ecdsa_sign(msghash, self.privkey)
-        return API.ecdsa_gen_sig(v, r, s)
+        signature = API.ecdsa_sign(message, self.privkey)
+        return signature
 
     def verify(self, msghash: bytes, signature: bytes) -> bool:
         """