Adds to DER format of ECDSA signature with extended ECDSA-Sig-Value and ECDSA-Full-R.

Author: gstarovo

src/ecdsa/der.py

@@ -151,6 +151,20 @@ def encode_number(n):
     return b"".join([int2byte(d) for d in b128_digits])
 
 
+def encode_boolean(b):
+    """
+    Encodes BOOLEAN acording to ASN.1 DER format.
+    The ASN.1 BOOLEAN type has two possible values: TRUE and FALSE.
+    True is encoded as ff", False is encoded as a zero.
+
+    :param boolean b: the boolean value to be encoded
+    :return: a byte string
+    :rtype: bytes
+    """
+
+    return b"\x01" + encode_length(1) + (b'\xff'if b else b'\x00')
+
+
 def is_sequence(string):
     return string and string[:1] == b"\x30"
 
@@ -234,6 +248,47 @@ def remove_octet_string(string):
     return body, rest
 
 
+def remove_boolean(string):
+    """
+    Removes the ASN.1 BOOLEAN type.
+    For BOOLEAN types, in DER FALSE is always encoded as zero
+    and TRUE is always encoded as ff.
+
+    :param bytes string: the boolean value to be encoded
+    :return: a boolean value and the rest of the string
+    :rtype: tuple(boolean, bytes)
+    """
+    if not string:
+        raise UnexpectedDER(
+            "Empty string is an invalid " "encoding of a boolean"
+        )
+    if string[:1] != b"\x01":
+        n = str_idx_as_int(string, 0)
+        raise UnexpectedDER("wanted type 'boolean' (0x01), got 0x%02x" % n)
+    length, lengthlength = read_length(string[1:])
+    body = string[1 + lengthlength : 1 + lengthlength + length]
+    rest = string[1 + lengthlength + length :]
+    if not body:
+        raise UnexpectedDER("Empty object identifier")
+    if len(body) != length:
+        raise UnexpectedDER(
+            "Length of object identifier longer than the provided buffer."
+        )
+    if length != 1:
+        raise UnexpectedDER(
+            "The contents octets of boolean shall consist of a single octet."
+        )
+    if body == b"\x00":
+        return False, rest
+    # the workaround due to instrumental, that
+    # saves the binary data as UF-8 string
+    # (0xff is an invalid start byte)
+    num = int(binascii.hexlify(body), 16)
+    if num == 0xFF:
+        return True, rest
+    raise UnexpectedDER("Invalid encoding of BOOLEAN.")
+
+
 def remove_object(string):
     if not string:
         raise UnexpectedDER(
@@ -292,8 +347,7 @@ def remove_integer(string):
         smsb = str_idx_as_int(numberbytes, 1)
         if smsb < 0x80:
             raise UnexpectedDER(
-                "Invalid encoding of integer, unnecessary "
-                "zero padding bytes"
+                "Invalid encoding of integer, unnecessary zero padding bytes"
             )
     return int(binascii.hexlify(numberbytes), 16), rest
 
@@ -393,8 +447,8 @@ def remove_bitstring(string, expect_unused=_sentry):
         raise UnexpectedDER("Empty string does not encode a bitstring")
     if expect_unused is _sentry:
         warnings.warn(
-            "Legacy call convention used, expect_unused= needs to be"
-            " specified",
+            "Legacy call convention used, "
+            "expect_unused= needs to be specified",
             DeprecationWarning,
         )
     num = str_idx_as_int(string, 0)

src/ecdsa/ecdsa.py

@@ -64,6 +64,7 @@
 modified as part of the python-ecdsa package.
 """
 
+import sys
 import warnings
 from six import int2byte
 from . import ellipticcurve
@@ -192,10 +193,24 @@ def verifies(self, hash, signature):
         n = G.order()
         r = signature.r
         s = signature.s
-        if r < 1 or r > n - 1:
-            return False
         if s < 1 or s > n - 1:
             return False
+
+        # check if the r value is a point
+        version = sys.version_info
+        if version[0] < 3 and version[1] < 7:
+            # memoryview was introduced in py 2.7
+            byte_objects = set((bytearray, bytes))
+        else:
+            byte_objects = set((bytearray, bytes, memoryview))
+        if type(r) in byte_objects:
+            point = ellipticcurve.AbstractPoint.from_bytes(
+                self.generator.curve(), r
+            )
+            r = point[0] % n
+
+        if r < 1 or r > n - 1:
+            return False
         c = numbertheory.inverse_mod(s, n)
         u1 = (hash * c) % n
         u2 = (r * c) % n
@@ -231,7 +246,7 @@ def __ne__(self, other):
         """Return False if the points are identical, True otherwise."""
         return not self == other
 
-    def sign(self, hash, random_k):
+    def sign(self, hash, random_k, accelerate=False):
         """Return a signature for the provided hash, using the provided
         random nonce.  It is absolutely vital that random_k be an unpredictable
         number in the range [1, self.public_key.point.order()-1].  If
@@ -267,6 +282,8 @@ def sign(self, hash, random_k):
         ) % n
         if s == 0:
             raise RSZeroError("amazingly unlucky random number s")
+        if accelerate:
+            return Signature(p1, s)
         return Signature(r, s)
 
 

src/ecdsa/keys.py

@@ -1318,6 +1318,7 @@ def sign_deterministic(
         hashfunc=None,
         sigencode=sigencode_string,
         extra_entropy=b"",
+        accelerate=False,
     ):
         """
         Create signature over data.
@@ -1354,6 +1355,10 @@ def sign_deterministic(
             number generator used in the RFC6979 process. Entirely optional.
             Ignored with EdDSA.
         :type extra_entropy: :term:`bytes-like object`
+        :param accelerate: an indicator for ECDSA sign operation to return
+            an ECPoint instead of a number of "r" parameter.
+            Applicable only for ECDSA key.
+        :type accelerate: boolean
 
         :return: encoded signature over `data`
         :rtype: bytes or sigencode function dependent type
@@ -1373,6 +1378,7 @@ def sign_deterministic(
             sigencode=sigencode,
             extra_entropy=extra_entropy,
             allow_truncate=True,
+            accelerate=accelerate,
         )
 
     def sign_digest_deterministic(
@@ -1382,6 +1388,7 @@ def sign_digest_deterministic(
         sigencode=sigencode_string,
         extra_entropy=b"",
         allow_truncate=False,
+        accelerate=False,
     ):
         """
         Create signature for digest using the deterministic RFC6979 algorithm.
@@ -1417,6 +1424,10 @@ def sign_digest_deterministic(
             bigger bit-size than the order of the curve, the extra bits (at
             the end of the digest) will be truncated. Use it when signing
             SHA-384 output using NIST256p or in similar situations.
+        :param accelerate: an indicator for ECDSA sign operation to return
+            an ECPoint instead of a number of "r" parameter.
+            Applicable only for ECDSA key.
+        :type accelerate: boolean
 
         :return: encoded signature for the `digest` hash
         :rtype: bytes or sigencode function dependent type
@@ -1447,6 +1458,7 @@ def simple_r_s(r, s, order):
                     sigencode=simple_r_s,
                     k=k,
                     allow_truncate=allow_truncate,
+                    accelerate=accelerate,
                 )
                 break
             except RSZeroError:
@@ -1462,6 +1474,7 @@ def sign(
         sigencode=sigencode_string,
         k=None,
         allow_truncate=True,
+        accelerate=False,
     ):
         """
         Create signature over data.
@@ -1525,6 +1538,10 @@ def sign(
             leak the key. Caller should try a better entropy source, retry with
             different ``k``, or use the
             :func:`~SigningKey.sign_deterministic` in such case.
+        :param accelerate: an indicator for ECDSA sign operation to return
+            an ECPoint instead of a number of "r" parameter.
+            Applicable only for ECDSA key.
+        :type accelerate: boolean
 
         :return: encoded signature of the hash of `data`
         :rtype: bytes or sigencode function dependent type
@@ -1534,7 +1551,9 @@ def sign(
         if isinstance(self.curve.curve, CurveEdTw):
             return self.sign_deterministic(data)
         h = hashfunc(data).digest()
-        return self.sign_digest(h, entropy, sigencode, k, allow_truncate)
+        return self.sign_digest(
+            h, entropy, sigencode, k, allow_truncate, accelerate
+        )
 
     def sign_digest(
         self,
@@ -1543,6 +1562,7 @@ def sign_digest(
         sigencode=sigencode_string,
         k=None,
         allow_truncate=False,
+        accelerate=False,
     ):
         """
         Create signature over digest using the probabilistic ECDSA algorithm.
@@ -1579,6 +1599,10 @@ def sign_digest(
             leak the key. Caller should try a better entropy source, retry with
             different 'k', or use the
             :func:`~SigningKey.sign_digest_deterministic` in such case.
+        :param accelerate: an indicator for ECDSA sign operation to return
+            an ECPoint instead of a number of "r" parameter.
+            Applicable only for ECDSA key.
+        :type accelerate: boolean
 
         :return: encoded signature for the `digest` hash
         :rtype: bytes or sigencode function dependent type
@@ -1591,10 +1615,10 @@ def sign_digest(
             self.curve,
             allow_truncate,
         )
-        r, s = self.sign_number(number, entropy, k)
+        r, s = self.sign_number(number, entropy, k, accelerate)
         return sigencode(r, s, self.privkey.order)
 
-    def sign_number(self, number, entropy=None, k=None):
+    def sign_number(self, number, entropy=None, k=None, accelerate=False):
         """
         Sign an integer directly.
 
@@ -1613,6 +1637,10 @@ def sign_number(self, number, entropy=None, k=None):
             leak the key. Caller should try a better entropy source, retry with
             different 'k', or use the
             :func:`~SigningKey.sign_digest_deterministic` in such case.
+        :param accelerate: an indicator for ECDSA sign operation to return
+            an ECPoint instead of a number of "r" parameter.
+            Applicable only for ECDSA key.
+        :type accelerate: boolean
 
         :return: the "r" and "s" parameters of the signature
         :rtype: tuple of ints
@@ -1627,5 +1655,5 @@ def sign_number(self, number, entropy=None, k=None):
             _k = randrange(order, entropy)
 
         assert 1 <= _k < order
-        sig = self.privkey.sign(number, _k)
+        sig = self.privkey.sign(number, _k, accelerate)
         return sig.r, sig.s

src/ecdsa/test_der.py

@@ -14,6 +14,7 @@
 from ._compat import str_idx_as_int
 from .curves import NIST256p, NIST224p
 from .der import (
+    remove_boolean,
     remove_integer,
     UnexpectedDER,
     read_length,
@@ -26,6 +27,7 @@
     remove_octet_string,
     remove_sequence,
     encode_implicit,
+    encode_boolean,
 )
 
 
@@ -565,6 +567,72 @@ def test_with_wrong_length(self):
         self.assertIn("Length longer", str(e.exception))
 
 
+class TestEncodeBoolean(unittest.TestCase):
+    def test_simple_true(self):
+        der = encode_boolean(True)
+        self.assertEqual(len(der), 3)
+        self.assertEqual(der, b"\x01\x01\xff")
+
+    def test_simle_false(self):
+        der = encode_boolean(False)
+        self.assertEqual(len(der), 3)
+        self.assertEqual(der, b"\x01\x01\x00")
+
+
+class TestRemoveBoolean(unittest.TestCase):
+    def test_simple_false(self):
+        data = b"\x01\x01\x00"
+        body, rest = remove_boolean(data)
+        self.assertEqual(body, False)
+        self.assertEqual(rest, b"")
+
+    def test_simple_true(self):
+        data = b"\x01\x01\xff"
+        body, rest = remove_boolean(data)
+        self.assertEqual(body, True)
+        self.assertEqual(rest, b"")
+
+    def test_empty_string(self):
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_boolean(b"")
+
+    def test_with_wrong_tag(self):
+        data = b"\x02\x01\x00"
+
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_boolean(data)
+
+        self.assertIn("wanted type 'boolean' (0x01)", str(e.exception))
+
+    def test_with_wrong_encoded_value(self):
+        data = b"\x01\x01\x01"
+
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_boolean(data)
+
+        self.assertIn("Invalid encoding of BOOLEAN", str(e.exception))
+
+    def test_empty_body(self):
+        data = b"\x01\x01"
+
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_boolean(data)
+
+        self.assertIn("Empty object identifier", str(e.exception))
+
+    def test_several_boolean_octets(self):
+        data = b"\x01\x02\x01\x01"
+
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_boolean(data)
+
+        self.assertIn(
+            "The contents octets of boolean "
+            "shall consist of a single octet",
+            str(e.exception),
+        )
+
+
 @st.composite
 def st_oid(draw, max_value=2**512, max_size=50):
     """

src/ecdsa/test_keys.py

@@ -1037,6 +1037,7 @@ def test_SigningKey_from_string(convert):
 key_bytes = unpem(prv_key_str)
 assert isinstance(key_bytes, bytes)
 
+
 # last two converters are for array.array of ints, those require input
 # that's multiple of 4, which no curve we support produces
 @pytest.mark.parametrize("convert", converters[:-2])