NIST SP 800-108 Counter Mode KDF (#2748)

* NIST SP 800-108 Counter Mode and Feedback Mode KDF

* CounterKDF unit tests

* Refactor to support multiple key based KDF modes.

* Extracting supported algorithms for KBKDF Counter Mode test vectors

* Adding support for different rlen and counter location in KBKDF

* support for multiple L lengths and 24 bit counter length.

* Adding KBKDF Documentation.

* Refactoring KBKDF to KBKDFHMAC to describe hash algorithm used.

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/hazmat/primitives/test_kbkdf_vectors.py b/tests/hazmat/primitives/test_kbkdf_vectors.py
new file mode 100644
index 00000000..c8263e2b
--- /dev/null
+++ b/tests/hazmat/primitives/test_kbkdf_vectors.py
@@ -0,0 +1,23 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+
+from __future__ import absolute_import, division, print_function
+
+import os
+
+import pytest
+
+from cryptography.hazmat.backends.interfaces import HMACBackend
+
+from .utils import generate_kbkdf_counter_mode_test
+from ...utils import load_nist_kbkdf_vectors
+
+
+@pytest.mark.requires_backend_interface(interface=HMACBackend)
+class TestCounterKDFCounterMode(object):
+    test_HKDFSHA1 = generate_kbkdf_counter_mode_test(
+        load_nist_kbkdf_vectors,
+        os.path.join("KDF"),
+        ["nist-800-108-KBKDF-CTR.txt"]
+    )