Interfaces for SCTs, feedback wanted (#3467)

* Stub API for SCTs, feedback wanted

* grr, flake8

* port this to being an ABC

* finish up the __init__

* Two necessary enums

* Roll this back

* Wrote some docs

* spell words correctly

* linky

* more details

* use the words UTC

* coverage

* Define MMD for the kids at some

* linky linky

1 files changed, 46 insertions, 0 deletions

diff --git a/src/cryptography/x509/certificate_transparency.py b/src/cryptography/x509/certificate_transparency.py
new file mode 100644
index 00000000..d00fe812
--- /dev/null
+++ b/src/cryptography/x509/certificate_transparency.py
@@ -0,0 +1,46 @@
+# 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 abc
+from enum import Enum
+
+import six
+
+
+class LogEntryType(Enum):
+    X509_CERTIFICATE = 0
+    PRE_CERTIFICATE = 1
+
+
+class Version(Enum):
+    v1 = 0
+
+
+@six.add_metaclass(abc.ABCMeta)
+class SignedCertificateTimestamp(object):
+    @abc.abstractproperty
+    def version(self):
+        """
+        Returns the SCT version.
+        """
+
+    @abc.abstractproperty
+    def log_id(self):
+        """
+        Returns an identifier indicating which log this SCT is for.
+        """
+
+    @abc.abstractproperty
+    def timestamp(self):
+        """
+        Returns the timestamp for this SCT.
+        """
+
+    @abc.abstractproperty
+    def entry_type(self):
+        """
+        Returns whether this is an SCT for a certificate or pre-certificate.
+        """