Updated documentation.
diff --git a/docs/hazmat/oath/hotp.rst b/docs/hazmat/oath/hotp.rst
index 1dee26b..7aff330 100644
--- a/docs/hazmat/oath/hotp.rst
+++ b/docs/hazmat/oath/hotp.rst
@@ -8,12 +8,12 @@
This module contains functions for generating and verifying one time password
values based on Hash-based message authentication codes (HMAC).
-.. class:: HOTP(secret, length, backend)
+.. class:: HOTP(key, length, backend)
- HOTP objects take a ``secret`` and ``length`` parameter. The ``secret``
+ HOTP objects take a ``key`` and ``length`` 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 is recommended to be at least a 6 digit value.
+ one time password and must be >= 6.
This is an implementation of :rfc:`4226`.
@@ -23,17 +23,22 @@
>>> from cryptography.hazmat.backends import default_backend
>>> from cryptography.hazmat.oath.hotp import HOTP
- >>> key = "12345678901234567890"
+ >>> key = b"12345678901234567890"
>>> hotp = HOTP(key, 6, backend=default_backend())
>>> hotp.generate(0)
'755224'
- >>> hotp.verify("755224", 0)
+ >>> hotp.verify(b"755224", 0)
- :param bytes secret: Secret key as ``bytes``.
+ :param bytes key: Secret key as ``bytes``. This value must be generated in a
+ cryptographically secure fashion and be at least 128 bits.
+ It is recommended that the key be 160 bits.
:param int length: Length of generated one time password as ``int``.
:param backend: A
:class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
provider.
+ :raises ValueError: This is raised if the provided ``key`` or ``length``
+ parameters are shorter than required.
+
.. method:: generate(counter)
@@ -44,4 +49,5 @@
:param bytes hotp: The one time password value to validate.
:param bytes counter: The counter value to validate against.
- :return: ``True`` if the one time password value is valid. ``False`` if otherwise.
+ :raises cryptography.exceptions.InvalidToken: This is raised when the supplied HOTP
+ does not match the expected HOTP.
diff --git a/tests/hazmat/oath/test_hotp.py b/tests/hazmat/oath/test_hotp.py
index 8a5aebd..4729265 100644
--- a/tests/hazmat/oath/test_hotp.py
+++ b/tests/hazmat/oath/test_hotp.py
@@ -53,7 +53,7 @@
hotp = HOTP(secret, 6, backend)
- assert hex(hotp._dynamic_truncate(counter))[2:] == truncated.decode()
+ assert hotp._dynamic_truncate(counter) == int(truncated.decode(), 16)
@pytest.mark.parametrize("params", vectors)
def test_generate(self, backend, params):