Made the rfc6979 module not dependent on the represetation of ECDSA generators.

Author: alex

ecdsa/keys.py

@@ -232,7 +232,8 @@ def sign_digest_deterministic(self, digest, hashfunc=None, sigencode=sigencode_s
         See RFC 6979 for more details.
         """
         secexp = self.privkey.secret_multiplier
-        k = rfc6979.generate_k(self.curve.generator, secexp, hashfunc, digest)
+        k = rfc6979.generate_k(
+            self.curve.generator.order(), secexp, hashfunc, digest)
 
         return self.sign_digest(digest, sigencode=sigencode, k=k)
 

ecdsa/rfc6979.py

@@ -51,18 +51,18 @@ def bits2octets(data, order):
     return number_to_string_crop(z2, order)
 
 # https://tools.ietf.org/html/rfc6979#section-3.2
-def generate_k(generator, secexp, hash_func, data):
+def generate_k(order, secexp, hash_func, data):
     '''
-        generator - ECDSA generator used in the signature
+        generator - order of the DSA generator used in the signature
         secexp - secure exponent (private key) in numeric form
         hash_func - reference to the same hash function used for generating hash
         data - hash in binary form of the signing data
     '''
 
-    qlen = bit_length(generator.order())
+    qlen = bit_length(order)
     holen = hash_func().digest_size
     rolen = (qlen + 7) / 8
-    bx = number_to_string(secexp, generator.order()) + bits2octets(data, generator.order())
+    bx = number_to_string(secexp, order) + bits2octets(data, order)
 
     # Step B
     v = b('\x01') * holen
@@ -96,7 +96,7 @@ def generate_k(generator, secexp, hash_func, data):
         # Step H3
         secret = bits2int(t, qlen)
 
-        if secret >= 1 and secret < generator.order():
+        if secret >= 1 and secret < order:
             return secret
 
         k = hmac.new(k, v+b('\x00'), hash_func).digest()

ecdsa/test_pyecdsa.py

@@ -57,7 +57,8 @@ def test_deterministic(self):
         priv = SigningKey.from_secret_exponent(secexp, SECP256k1, sha256)
         pub = priv.get_verifying_key()
 
-        k = rfc6979.generate_k(SECP256k1.generator, secexp, sha256, sha256(data).digest())
+        k = rfc6979.generate_k(
+            SECP256k1.generator.order(), secexp, sha256, sha256(data).digest())
 
         sig1 = priv.sign(data, k=k)
         self.assertTrue(pub.verify(sig1, data))
@@ -522,7 +523,7 @@ def OFF_test_prove_uniformity(self):
 class RFC6979(unittest.TestCase):
     # https://tools.ietf.org/html/rfc6979#appendix-A.1
     def _do(self, generator, secexp, hsh, hash_func, expected):
-        actual = rfc6979.generate_k(generator, secexp, hash_func, hsh)
+        actual = rfc6979.generate_k(generator.order(), secexp, hash_func, hsh)
         self.assertEqual(expected, actual)
 
     def test_SECP256k1(self):