Merge pull request #689 from dreid/twofactor-cleanup

Cleanup twofactor docs and code.

6 files changed, 36 insertions, 35 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index b87b8722..bbbcfb1f 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -5,6 +5,7 @@ Changelog
 ~~~~~~~~~~~~~~~~
 
 * Added :class:`~cryptography.hazmat.primitives.twofactor.hotp.HOTP`.
+* Added :class:`~cryptography.hazmat.primitives.twofactor.totp.TOTP`.
 
 0.2.1 - 2014-02-22
 ~~~~~~~~~~~~~~~~~~
diff --git a/cryptography/hazmat/primitives/twofactor/hotp.py b/cryptography/hazmat/primitives/twofactor/hotp.py
index e806c7ef..24f5f465 100644
--- a/cryptography/hazmat/primitives/twofactor/hotp.py
+++ b/cryptography/hazmat/primitives/twofactor/hotp.py
@@ -24,7 +24,6 @@ from cryptography.hazmat.primitives.hashes import SHA1, SHA256, SHA512
 
 class HOTP(object):
     def __init__(self, key, length, algorithm, backend):
-
         if len(key) < 16:
             raise ValueError("Key length has to be at least 128 bits.")
 
diff --git a/cryptography/hazmat/primitives/twofactor/totp.py b/cryptography/hazmat/primitives/twofactor/totp.py
index be84b477..0630de69 100644
--- a/cryptography/hazmat/primitives/twofactor/totp.py
+++ b/cryptography/hazmat/primitives/twofactor/totp.py
@@ -20,7 +20,6 @@ from cryptography.hazmat.primitives.twofactor.hotp import HOTP
 
 class TOTP(object):
     def __init__(self, key, length, algorithm, time_step, backend):
-
         self._time_step = time_step
         self._hotp = HOTP(key, length, algorithm, backend)
 
diff --git a/docs/hazmat/primitives/twofactor.rst b/docs/hazmat/primitives/twofactor.rst
index 06be151e..3df1a147 100644
--- a/docs/hazmat/primitives/twofactor.rst
+++ b/docs/hazmat/primitives/twofactor.rst
@@ -19,8 +19,8 @@ codes (HMAC).
 
     HOTP objects take a ``key``, ``length`` and ``algorithm`` parameter. The
     ``key`` should be randomly generated bytes and is recommended to be 160
-    bits in length. The ``length`` parameter controls the length of the generated
-    one time password and must be >= 6 and <= 8.
+    bits in length. The ``length`` parameter controls the length of the
+    generated one time password and must be >= 6 and <= 8.
 
     This is an implementation of :rfc:`4226`.
 
@@ -45,44 +45,48 @@ codes (HMAC).
     :param backend: A
         :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
         provider.
-    :raises ValueError: This is raised if the provided ``key`` is shorter than 128 bits
-                        or if the ``length`` parameter is not 6, 7 or 8.
-    :raises UnsupportedAlgorithm: This is raised if the provided ``algorithm`` is not
-                                  :class:`~cryptography.hazmat.primitives.hashes.SHA1()`,
-                                  :class:`~cryptography.hazmat.primitives.hashes.SHA256()`
-                                  or :class:`~cryptography.hazmat.primitives.hashes.SHA512()`.
+    :raises ValueError: This is raised if the provided ``key`` is shorter than
+        128 bits or if the ``length`` parameter is not 6, 7 or 8.
+    :raises UnsupportedAlgorithm: This is raised if the provided ``algorithm``
+        is not :class:`~cryptography.hazmat.primitives.hashes.SHA1()`,
+        :class:`~cryptography.hazmat.primitives.hashes.SHA256()` or
+        :class:`~cryptography.hazmat.primitives.hashes.SHA512()`.
 
     .. method:: generate(counter)
 
-        :param int counter: The counter value used to generate the one time password.
+        :param int counter: The counter value used to generate the one time
+            password.
         :return bytes: A one time password value.
 
     .. method:: verify(hotp, counter)
 
         :param bytes hotp: The one time password value to validate.
         :param int counter: The counter value to validate against.
-        :raises cryptography.exceptions.InvalidToken: This is raised when the supplied HOTP
-                                                      does not match the expected HOTP.
+        :raises cryptography.exceptions.InvalidToken: This is raised when the
+            supplied HOTP does not match the expected HOTP.
 
 Throttling
 ~~~~~~~~~~
 
-Due to the fact that the HOTP algorithm generates rather short tokens that are 6 - 8 digits
-long, brute force attacks are possible. It is highly recommended that the server that
-validates the token implement a throttling scheme that locks out the account for a period of
-time after a number of failed attempts. The number of allowed attempts should be as low as
-possible while still ensuring that usability is not significantly impacted.
+Due to the fact that the HOTP algorithm generates rather short tokens that are
+6 - 8 digits long, brute force attacks are possible. It is highly recommended
+that the server that validates the token implement a throttling scheme that
+locks out the account for a period of time after a number of failed attempts.
+The number of allowed attempts should be as low as possible while still
+ensuring that usability is not significantly impacted.
 
 Re-synchronization of the Counter
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The server's counter value should only be incremented on a successful HOTP authentication.
-However, the counter on the client is incremented every time a new HOTP value is requested.
-This can lead to the counter value being out of synchronization between the client and server.
+The server's counter value should only be incremented on a successful HOTP
+authentication. However, the counter on the client is incremented every time a
+new HOTP value is requested. This can lead to the counter value being out of
+synchronization between the client and server.
 
-Due to this, it is highly recommended that the server sets a look-ahead window that allows the
-server to calculate the next ``x`` HOTP values and check them against the supplied HOTP value.
-This can be accomplished with something similar to the following code.
+Due to this, it is highly recommended that the server sets a look-ahead window
+that allows the server to calculate the next ``x`` HOTP values and check them
+against the supplied HOTP value. This can be accomplished with something
+similar to the following code.
 
 .. code-block:: python
 
@@ -91,7 +95,7 @@ This can be accomplished with something similar to the following code.
         correct_counter = None
 
         otp = HOTP(key, 6, default_backend())
-        for count in range(counter, counter+look_ahead):
+        for count in range(counter, counter + look_ahead):
             try:
                 otp.verify(hotp, count)
                 correct_counter = count
@@ -136,12 +140,12 @@ This can be accomplished with something similar to the following code.
     :param backend: A
         :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
         provider.
-    :raises ValueError: This is raised if the provided ``key`` is shorter than 128 bits
-                        or if the ``length`` parameter is not 6, 7 or 8.
-    :raises UnsupportedAlgorithm: This is raised if the provided ``algorithm`` is not
-                                  :class:`~cryptography.hazmat.primitives.hashes.SHA1()`,
-                                  :class:`~cryptography.hazmat.primitives.hashes.SHA256()`
-                                  or :class:`~cryptography.hazmat.primitives.hashes.SHA512()`.
+    :raises ValueError: This is raised if the provided ``key`` is shorter than
+        128 bits or if the ``length`` parameter is not 6, 7 or 8.
+    :raises UnsupportedAlgorithm: This is raised if the provided ``algorithm``
+        is not :class:`~cryptography.hazmat.primitives.hashes.SHA1()`,
+        :class:`~cryptography.hazmat.primitives.hashes.SHA256()` or
+        :class:`~cryptography.hazmat.primitives.hashes.SHA512()`.
 
     .. method:: generate(time)
 
@@ -152,5 +156,5 @@ This can be accomplished with something similar to the following code.
 
         :param bytes totp: The one time password value to validate.
         :param int time: The time value to validate against.
-        :raises cryptography.exceptions.InvalidToken: This is raised when the supplied TOTP
-                                                      does not match the expected TOTP.
+        :raises cryptography.exceptions.InvalidToken: This is raised when the
+            supplied TOTP does not match the expected TOTP.
diff --git a/tests/hazmat/primitives/twofactor/test_hotp.py b/tests/hazmat/primitives/twofactor/test_hotp.py
index 8f687ebb..7c584271 100644
--- a/tests/hazmat/primitives/twofactor/test_hotp.py
+++ b/tests/hazmat/primitives/twofactor/test_hotp.py
@@ -31,7 +31,6 @@ vectors = load_vectors_from_file(
 )
 @pytest.mark.hmac
 class TestHOTP(object):
-
     def test_invalid_key_length(self, backend):
         secret = os.urandom(10)
 
diff --git a/tests/hazmat/primitives/twofactor/test_totp.py b/tests/hazmat/primitives/twofactor/test_totp.py
index 8877a70a..a4a108bc 100644
--- a/tests/hazmat/primitives/twofactor/test_totp.py
+++ b/tests/hazmat/primitives/twofactor/test_totp.py
@@ -24,7 +24,6 @@ vectors = load_vectors_from_file(
 
 @pytest.mark.hmac
 class TestTOTP(object):
-
     @pytest.mark.supported(
         only_if=lambda backend: backend.hmac_supported(hashes.SHA1()),
         skip_message="Does not support HMAC-SHA1."