diff --git a/.travis.yml b/.travis.yml
index a70bb8c..b77a7b7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -42,10 +42,9 @@
         use_notice: true
         skip_join: true
 
-# When building an exclude matrix on Travis you must supply
-# the exact variable combinations you want to exclude from
-# your build matrix. There is no (current) way to make this
-# less verbose.
+# When building an exclude matrix on Travis you must supply the exact variable
+# combinations you want to exclude from your build matrix. There is no
+# (current) way to make this less verbose.
 matrix:
     exclude:
         - os: osx
diff --git a/cryptography/hazmat/primitives/interfaces.py b/cryptography/hazmat/primitives/interfaces.py
index 4fa2457..460aab7 100644
--- a/cryptography/hazmat/primitives/interfaces.py
+++ b/cryptography/hazmat/primitives/interfaces.py
@@ -185,6 +185,12 @@
         """
 
     @abc.abstractproperty
+    def private_exponent(self):
+        """
+        The private exponent of the RSA key.
+        """
+
+    @abc.abstractproperty
     def key_size(self):
         """
         The bit length of the public modulus.
@@ -217,7 +223,8 @@
     @abc.abstractproperty
     def d(self):
         """
-        The private exponent. This can be calculated using p and q.
+        The private exponent. This can be calculated using p and q. Alias for
+        private_exponent.
         """
 
     @abc.abstractproperty
diff --git a/docs/hazmat/primitives/interfaces.rst b/docs/hazmat/primitives/interfaces.rst
index 7fef1c1..cbca5ed 100644
--- a/docs/hazmat/primitives/interfaces.rst
+++ b/docs/hazmat/primitives/interfaces.rst
@@ -130,6 +130,12 @@
 
         The public exponent.
 
+    .. attribute:: private_exponent
+
+        :type: int
+
+        The private exponent.
+
     .. attribute:: key_size
 
         :type: int
@@ -152,7 +158,7 @@
 
         :type: int
 
-        The private exponent.
+        The private exponent. Alias for :attr:`private_exponent`.
 
     .. attribute:: n