TOTP implementation mostly finalize

TOTP module reworked drastically. Should have committed this a long time ago.
Now have what is (hopefully) the final API for the TOTP module.

* Supports TOTP & HOTP
* Supports URI rendering & parsing
* Highlevel methods to handle state management, client clock skew estimation, etc.
* Unittests mostly complete (a few edge cases)
* Persistent serialization supports encrypting secrets with a password,
  to mitigate exposure of storage medium.
* Basic API documentation.

Should be suitable for following use-cases:

* lowlevel methods for implementing HOTP/TOTP on server
* highlevel methods for implementing HOTP/TOTP on server,
  and letting them handle details of tracking client state.
* methods for implementing an HOTP / TOTP client.

1 files changed, 15 insertions, 0 deletions

diff --git a/passlib/exc.py b/passlib/exc.py
index daac72a..5c2e548 100644
--- a/passlib/exc.py
+++ b/passlib/exc.py
@@ -39,6 +39,21 @@ class PasswordSizeError(ValueError):
     # this also prevents a glibc crypt segfault issue, detailed here ...
     # http://www.openwall.com/lists/oss-security/2011/11/15/1
 
+class TokenReuseError(ValueError):
+    """Error raised by various methods in :mod:`passlib.totp` if a token is reused.
+    This exception derives from :exc:`!ValueError`.
+
+    .. versionadded:: 1.7
+    """
+
+    #: optional value indicating when current counter period will end,
+    #: and a new token can be generated.
+    expire_time = None
+
+    def __init__(self, *args, **kwds):
+        self.expire_time = kwds.pop("expire_time", None)
+        ValueError.__init__(self, *args, **kwds)
+
 #=============================================================================
 # warnings
 #=============================================================================