Don't expose extract and expand on this class yet because we don't know how best to expose verify functionality, continue testing the stages using the private methods.

3 files changed, 2 insertions, 36 deletions

diff --git a/cryptography/hazmat/primitives/kdf/hkdf.py b/cryptography/hazmat/primitives/kdf/hkdf.py
index 2b5ba815..ae24f676 100644
--- a/cryptography/hazmat/primitives/kdf/hkdf.py
+++ b/cryptography/hazmat/primitives/kdf/hkdf.py
@@ -57,27 +57,11 @@ class HKDF(object):
 
         self._used = False
 
-    def extract(self, key_material):
-        if self._used:
-            raise exceptions.AlreadyFinalized
-
-        self._used = True
-
-        return self._extract(key_material)
-
     def _extract(self, key_material):
         h = hmac.HMAC(self._salt, self._algorithm, backend=self._backend)
         h.update(key_material)
         return h.finalize()
 
-    def expand(self, key_material):
-        if self._used:
-            raise exceptions.AlreadyFinalized
-
-        self._used = True
-
-        return self._expand(key_material)
-
     def _expand(self, key_material):
         output = [b""]
         counter = 1
diff --git a/tests/hazmat/primitives/test_hkdf.py b/tests/hazmat/primitives/test_hkdf.py
index f3345b05..66993f0e 100644
--- a/tests/hazmat/primitives/test_hkdf.py
+++ b/tests/hazmat/primitives/test_hkdf.py
@@ -71,24 +71,6 @@ class TestHKDF(object):
             backend=backend
         )
 
-        hkdf.extract(b"\x01" * 16)
-
-        with pytest.raises(exceptions.AlreadyFinalized):
-            hkdf.extract(b"\x02" * 16)
-
-        hkdf = HKDF(
-            hashes.SHA256(),
-            16,
-            salt=None,
-            info=None,
-            backend=backend
-        )
-
-        hkdf.expand(b"\x01" * 16)
-
-        with pytest.raises(exceptions.AlreadyFinalized):
-            hkdf.expand(b"\x02" * 16)
-
     def test_verify(self, backend):
         hkdf = HKDF(
             hashes.SHA256(),
diff --git a/tests/hazmat/primitives/utils.py b/tests/hazmat/primitives/utils.py
index 2584272a..5a8dc3ab 100644
--- a/tests/hazmat/primitives/utils.py
+++ b/tests/hazmat/primitives/utils.py
@@ -326,7 +326,7 @@ def hkdf_extract_test(backend, algorithm, params):
         backend=backend
     )
 
-    prk = hkdf.extract(binascii.unhexlify(params["ikm"]))
+    prk = hkdf._extract(binascii.unhexlify(params["ikm"]))
 
     assert prk == binascii.unhexlify(params["prk"])
 
@@ -340,7 +340,7 @@ def hkdf_expand_test(backend, algorithm, params):
         backend=backend
     )
 
-    okm = hkdf.expand(binascii.unhexlify(params["prk"]))
+    okm = hkdf._expand(binascii.unhexlify(params["prk"]))
 
     assert okm == binascii.unhexlify(params["okm"])