Add DSA verification docs
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 43e5d8f..f15bc28 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -14,6 +14,7 @@
     It implements the following interfaces:
 
     * :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
     * :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.PBKDF2HMACBackend`