add support for encoding/decoding elliptic curve points

Based on the work of @ronf in #2346.

1 files changed, 71 insertions, 2 deletions

diff --git a/tests/hazmat/primitives/test_asym_utils.py b/tests/hazmat/primitives/test_asym_utils.py
index b9971137..c713e9c6 100644
--- a/tests/hazmat/primitives/test_asym_utils.py
+++ b/tests/hazmat/primitives/test_asym_utils.py
@@ -4,11 +4,14 @@
 
 from __future__ import absolute_import, division, print_function
 
+import binascii
+
 import pytest
 
+from cryptography.hazmat.primitives.asymmetric import ec
 from cryptography.hazmat.primitives.asymmetric.utils import (
-    decode_dss_signature, decode_rfc6979_signature,
-    encode_dss_signature, encode_rfc6979_signature
+    decode_dss_signature, decode_ec_point, decode_rfc6979_signature,
+    encode_dss_signature, encode_ec_point, encode_rfc6979_signature
 )
 
 
@@ -76,3 +79,69 @@ def test_decode_dss_invalid_asn1():
         # This is the BER "end-of-contents octets," which older versions of
         # pyasn1 are wrongly willing to return from top-level DER decoding.
         decode_dss_signature(b"\x00\x00")
+
+
+def test_encode_ec_point_none():
+    assert encode_ec_point(ec.SECP384R1(), None, 100) == b"\x00"
+
+
+def test_encode_wrong_curve_type():
+    with pytest.raises(TypeError):
+        encode_ec_point("notacurve", 3, 4)
+
+
+def test_encode_ec_point():
+    # secp256r1 point
+    x = int(
+        '233ea3b0027127084cd2cd336a13aeef69c598d8af61369a36454a17c6c22aec', 16
+    )
+    y = int(
+        '3ea2c10a84153862be4ec82940f0543f9ba866af9751a6ee79d38460b35f442e', 16
+    )
+    data = encode_ec_point(ec.SECP256R1(), x, y)
+    assert data == binascii.unhexlify(
+        "04233ea3b0027127084cd2cd336a13aeef69c598d8af61369a36454a17c6c22aec3ea"
+        "2c10a84153862be4ec82940f0543f9ba866af9751a6ee79d38460b35f442e"
+    )
+
+
+def test_decode_ec_point_none():
+    assert decode_ec_point(ec.SECP384R1(), b"\x00") == (None, None)
+
+
+def test_decode_ec_point():
+    # secp256r1 point
+    data = binascii.unhexlify(
+        "04233ea3b0027127084cd2cd336a13aeef69c598d8af61369a36454a17c6c22aec3ea"
+        "2c10a84153862be4ec82940f0543f9ba866af9751a6ee79d38460b35f442e"
+    )
+    x, y = decode_ec_point(ec.SECP256R1(), data)
+    assert x == int(
+        '233ea3b0027127084cd2cd336a13aeef69c598d8af61369a36454a17c6c22aec', 16
+    )
+    assert y == int(
+        '3ea2c10a84153862be4ec82940f0543f9ba866af9751a6ee79d38460b35f442e', 16
+    )
+
+
+def test_decode_ec_point_invalid_length():
+    bad_data = binascii.unhexlify(
+        "04233ea3b0027127084cd2cd336a13aeef69c598d8af61369a36454a17c6c22aec3ea"
+        "2c10a84153862be4ec82940f0543f9ba866af9751a6ee79d38460"
+    )
+    with pytest.raises(ValueError):
+        decode_ec_point(ec.SECP384R1(), bad_data)
+
+
+def test_decode_ec_point_unsupported_point_type():
+    # set to point type 2.
+    unsupported_type = binascii.unhexlify(
+        "02233ea3b0027127084cd2cd336a13aeef69c598d8af61369a36454a17c6c22aec3e"
+    )
+    with pytest.raises(ValueError):
+        decode_ec_point(ec.SECP256R1(), unsupported_type)
+
+
+def test_decode_wrong_curve_type():
+    with pytest.raises(TypeError):
+        decode_ec_point("notacurve", b"\x02data")