Brainpool curves (#4129)
* added brainpool ec-curves key_length >= 256bit
* limit brainpool curves to the set that appear required + docs
* oops
* typos all around me
* add brainpool ECDH kex tests
* switch to using rfc 7027 vectors
* review feedback
* empty commits are the best
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 79ce603..2f8924f 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -10,6 +10,10 @@
* **BACKWARDS INCOMPATIBLE:** Support for Python 2.6 has been dropped.
* Resolved a bug in ``HKDF`` that incorrectly constrained output size.
+* Added :class:`~cryptography.hazmat.primitives.asymmetric.ec.BrainpoolP256R1`,
+ :class:`~cryptography.hazmat.primitives.asymmetric.ec.BrainpoolP384R1`, and
+ :class:`~cryptography.hazmat.primitives.asymmetric.ec.BrainpoolP512R1` to
+ support inter-operating with systems like German smart meters.
* Added token rotation support to :doc:`Fernet </fernet>` with
:meth:`~cryptography.fernet.MultiFernet.rotate`.
* Fixed a memory leak in
diff --git a/docs/hazmat/primitives/asymmetric/ec.rst b/docs/hazmat/primitives/asymmetric/ec.rst
index 5d6251f..edcfdfc 100644
--- a/docs/hazmat/primitives/asymmetric/ec.rst
+++ b/docs/hazmat/primitives/asymmetric/ec.rst
@@ -414,6 +414,28 @@
SECG curve ``secp256k1``.
+.. class:: BrainpoolP256R1
+
+ .. versionadded:: 2.2
+
+ Brainpool curve specified in :rfc:`5639`. These curves are discouraged
+ for new systems.
+
+.. class:: BrainpoolP384R1
+
+ .. versionadded:: 2.2
+
+ Brainpool curve specified in :rfc:`5639`. These curves are discouraged
+ for new systems.
+
+.. class:: BrainpoolP512R1
+
+ .. versionadded:: 2.2
+
+ Brainpool curve specified in :rfc:`5639`. These curves are discouraged
+ for new systems.
+
+
Key Interfaces
~~~~~~~~~~~~~~
diff --git a/src/cryptography/hazmat/primitives/asymmetric/ec.py b/src/cryptography/hazmat/primitives/asymmetric/ec.py
index 7931b08..83266bb 100644
--- a/src/cryptography/hazmat/primitives/asymmetric/ec.py
+++ b/src/cryptography/hazmat/primitives/asymmetric/ec.py
@@ -228,6 +228,24 @@
key_size = 192
+@utils.register_interface(EllipticCurve)
+class BrainpoolP256R1(object):
+ name = "brainpoolP256r1"
+ key_size = 256
+
+
+@utils.register_interface(EllipticCurve)
+class BrainpoolP384R1(object):
+ name = "brainpoolP384r1"
+ key_size = 384
+
+
+@utils.register_interface(EllipticCurve)
+class BrainpoolP512R1(object):
+ name = "brainpoolP512r1"
+ key_size = 512
+
+
_CURVE_TYPES = {
"prime192v1": SECP192R1,
"prime256v1": SECP256R1,
@@ -250,6 +268,10 @@
"sect283r1": SECT283R1,
"sect409r1": SECT409R1,
"sect571r1": SECT571R1,
+
+ "brainpoolP256r1": BrainpoolP256R1,
+ "brainpoolP384r1": BrainpoolP384R1,
+ "brainpoolP512r1": BrainpoolP512R1,
}
diff --git a/tests/hazmat/primitives/test_ec.py b/tests/hazmat/primitives/test_ec.py
index 02b1cdc..1b491a1 100644
--- a/tests/hazmat/primitives/test_ec.py
+++ b/tests/hazmat/primitives/test_ec.py
@@ -26,7 +26,7 @@
from ...doubles import DummyKeySerializationEncryption
from ...utils import (
load_fips_ecdsa_key_pair_vectors, load_fips_ecdsa_signing_vectors,
- load_kasvs_ecdh_vectors, load_vectors_from_file,
+ load_kasvs_ecdh_vectors, load_nist_vectors, load_vectors_from_file,
raises_unsupported_algorithm
)
@@ -1101,6 +1101,33 @@
else:
assert z == vector['Z']
+ @pytest.mark.parametrize(
+ "vector",
+ load_vectors_from_file(
+ os.path.join("asymmetric", "ECDH", "brainpool.txt"),
+ load_nist_vectors
+ )
+ )
+ def test_brainpool_kex(self, backend, vector):
+ curve = ec._CURVE_TYPES[vector['curve'].decode('ascii')]
+ _skip_exchange_algorithm_unsupported(backend, ec.ECDH(), curve)
+ key = ec.EllipticCurvePrivateNumbers(
+ int(vector['da'], 16),
+ ec.EllipticCurvePublicNumbers(
+ int(vector['x_qa'], 16), int(vector['y_qa'], 16), curve()
+ )
+ ).private_key(backend)
+ peer = ec.EllipticCurvePrivateNumbers(
+ int(vector['db'], 16),
+ ec.EllipticCurvePublicNumbers(
+ int(vector['x_qb'], 16), int(vector['y_qb'], 16), curve()
+ )
+ ).private_key(backend)
+ shared_secret = key.exchange(ec.ECDH(), peer.public_key())
+ assert shared_secret == binascii.unhexlify(vector["x_z"])
+ shared_secret_2 = peer.exchange(ec.ECDH(), key.public_key())
+ assert shared_secret_2 == binascii.unhexlify(vector["x_z"])
+
def test_exchange_unsupported_algorithm(self, backend):
_skip_curve_unsupported(backend, ec.SECP256R1())