Add ScryptParams

duniterpy/key/__init__.py

-from .signing_key import SigningKey
+from .signing_key import SigningKey, ScryptParams
 from .verifying_key import VerifyingKey
 from .encryption_key import SecretKey, PublicKey
\ No newline at end of file

duniterpy/key/signing_key.py

@@ -11,11 +11,12 @@ from .base58 import Base58Encoder
 
 SEED_LENGTH = 32  # Length of the key
 crypto_sign_BYTES = 64
-SCRYPT_PARAMS = {'N': 4096,
-                 'r': 16,
-                 'p': 1
-                 }
 
+class ScryptParams:
+    def __init__(self, N, r, p):
+        self.N = N
+        self.r = r
+        self.p = p
 
 def _ensure_bytes(data):
     if isinstance(data, str):
@@ -25,11 +26,11 @@ def _ensure_bytes(data):
 
 
 class SigningKey(libnacl.sign.Signer):
-    def __init__(self, salt, password):
+    def __init__(self, salt, password, scrypt_params):
         salt = _ensure_bytes(salt)
         password = _ensure_bytes(password)
         seed = scrypt(password, salt,
-                    SCRYPT_PARAMS['N'], SCRYPT_PARAMS['r'], SCRYPT_PARAMS['p'],
+                      scrypt_params.N, scrypt_params.r, scrypt_params.p,
                       SEED_LENGTH)
 
         super().__init__(seed)

tests/key/test_verifying_key.py

-from duniterpy.key import VerifyingKey, SigningKey
+from duniterpy.key import VerifyingKey, SigningKey, ScryptParams
 from duniterpy.documents import Peer
 import unittest
 
 
 class TestVerifyingKey(unittest.TestCase):
     def test_from_sign_to_verify(self):
-        sign_key = SigningKey("saltsalt", "passwordpassword")
+        sign_key = SigningKey("saltsalt", "passwordpassword", ScryptParams(4096, 16, 1))
         verify_key = VerifyingKey(sign_key.pubkey)
         self.assertEqual(verify_key.vk, sign_key.vk)