Merge pull request #980 from reaperhulk/dsa-sig-serializer

dss_sig_value: Pure python conversion of (r, s) to byte stream

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/utils.py b/tests/utils.py
index 60b6f5a2..5c0e2343 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -18,6 +18,9 @@ import collections
 import re
 from contextlib import contextmanager
 
+from pyasn1.codec.der import encoder
+from pyasn1.type import namedtype, univ
+
 import pytest
 
 import six
@@ -80,6 +83,20 @@ def raises_unsupported_algorithm(reason):
     assert exc_info.value._reason is reason
 
 
+class _DSSSigValue(univ.Sequence):
+    componentType = namedtype.NamedTypes(
+        namedtype.NamedType('r', univ.Integer()),
+        namedtype.NamedType('s', univ.Integer())
+    )
+
+
+def der_encode_dsa_signature(r, s):
+    sig = _DSSSigValue()
+    sig.setComponentByName('r', r)
+    sig.setComponentByName('s', s)
+    return encoder.encode(sig)
+
+
 def load_vectors_from_file(filename, loader):
     with cryptography_vectors.open_vector_file(filename) as vector_file:
         return loader(vector_file)