diff --git a/cryptography/__init__.py b/cryptography/__init__.py
index f37bd22..599bb05 100644
--- a/cryptography/__init__.py
+++ b/cryptography/__init__.py
@@ -10,6 +10,9 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
 from cryptography.__about__ import (
     __title__, __summary__, __uri__, __version__, __author__, __email__,
     __license__, __copyright__
diff --git a/cryptography/exceptions.py b/cryptography/exceptions.py
index a26dbe1..d7c867d 100644
--- a/cryptography/exceptions.py
+++ b/cryptography/exceptions.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 
 class UnsupportedAlgorithm(Exception):
     pass
diff --git a/cryptography/fernet.py b/cryptography/fernet.py
index 71a9fad..28d9c92 100644
--- a/cryptography/fernet.py
+++ b/cryptography/fernet.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import base64
 import binascii
 import os
diff --git a/cryptography/hazmat/__init__.py b/cryptography/hazmat/__init__.py
index 55c925c..2f42057 100644
--- a/cryptography/hazmat/__init__.py
+++ b/cryptography/hazmat/__init__.py
@@ -10,3 +10,5 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/cryptography/hazmat/backends/__init__.py b/cryptography/hazmat/backends/__init__.py
index 406b37e..59d1bc6 100644
--- a/cryptography/hazmat/backends/__init__.py
+++ b/cryptography/hazmat/backends/__init__.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 from cryptography.hazmat.backends import openssl
 from cryptography.hazmat.backends.multibackend import MultiBackend
 from cryptography.hazmat.bindings.commoncrypto.binding import (
diff --git a/cryptography/hazmat/backends/commoncrypto/__init__.py b/cryptography/hazmat/backends/commoncrypto/__init__.py
index 64a1c01..f080394 100644
--- a/cryptography/hazmat/backends/commoncrypto/__init__.py
+++ b/cryptography/hazmat/backends/commoncrypto/__init__.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 from cryptography.hazmat.backends.commoncrypto.backend import backend
 
 
diff --git a/cryptography/hazmat/backends/openssl/__init__.py b/cryptography/hazmat/backends/openssl/__init__.py
index a8dfad0..25885e1 100644
--- a/cryptography/hazmat/backends/openssl/__init__.py
+++ b/cryptography/hazmat/backends/openssl/__init__.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 from cryptography.hazmat.backends.openssl.backend import backend
 
 
diff --git a/cryptography/hazmat/bindings/__init__.py b/cryptography/hazmat/bindings/__init__.py
index 55c925c..2f42057 100644
--- a/cryptography/hazmat/bindings/__init__.py
+++ b/cryptography/hazmat/bindings/__init__.py
@@ -10,3 +10,5 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/cryptography/hazmat/bindings/commoncrypto/__init__.py b/cryptography/hazmat/bindings/commoncrypto/__init__.py
index 55c925c..2f42057 100644
--- a/cryptography/hazmat/bindings/commoncrypto/__init__.py
+++ b/cryptography/hazmat/bindings/commoncrypto/__init__.py
@@ -10,3 +10,5 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/cryptography/hazmat/bindings/commoncrypto/binding.py b/cryptography/hazmat/bindings/commoncrypto/binding.py
index 45c0eaa..ee80942 100644
--- a/cryptography/hazmat/bindings/commoncrypto/binding.py
+++ b/cryptography/hazmat/bindings/commoncrypto/binding.py
@@ -14,6 +14,7 @@
 from __future__ import absolute_import, division, print_function
 
 import sys
+import platform
 
 from cryptography.hazmat.bindings.utils import build_ffi
 
@@ -46,4 +47,5 @@
 
     @classmethod
     def is_available(cls):
-        return sys.platform == "darwin"
+        return sys.platform == "darwin" and list(map(
+            int, platform.mac_ver()[0].split("."))) >= [10, 8, 0]
diff --git a/cryptography/hazmat/bindings/commoncrypto/common_cryptor.py b/cryptography/hazmat/bindings/commoncrypto/common_cryptor.py
index 8f03bc3..9bd03a7 100644
--- a/cryptography/hazmat/bindings/commoncrypto/common_cryptor.py
+++ b/cryptography/hazmat/bindings/commoncrypto/common_cryptor.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <CommonCrypto/CommonCryptor.h>
 """
diff --git a/cryptography/hazmat/bindings/commoncrypto/common_digest.py b/cryptography/hazmat/bindings/commoncrypto/common_digest.py
index ec0fcc9..c59200c 100644
--- a/cryptography/hazmat/bindings/commoncrypto/common_digest.py
+++ b/cryptography/hazmat/bindings/commoncrypto/common_digest.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <CommonCrypto/CommonDigest.h>
 """
diff --git a/cryptography/hazmat/bindings/commoncrypto/common_hmac.py b/cryptography/hazmat/bindings/commoncrypto/common_hmac.py
index a4bf900..4f54b62 100644
--- a/cryptography/hazmat/bindings/commoncrypto/common_hmac.py
+++ b/cryptography/hazmat/bindings/commoncrypto/common_hmac.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <CommonCrypto/CommonHMAC.h>
 """
diff --git a/cryptography/hazmat/bindings/commoncrypto/common_key_derivation.py b/cryptography/hazmat/bindings/commoncrypto/common_key_derivation.py
index 85def1e..e8cc03e 100644
--- a/cryptography/hazmat/bindings/commoncrypto/common_key_derivation.py
+++ b/cryptography/hazmat/bindings/commoncrypto/common_key_derivation.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <CommonCrypto/CommonKeyDerivation.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/__init__.py b/cryptography/hazmat/bindings/openssl/__init__.py
index 55c925c..2f42057 100644
--- a/cryptography/hazmat/bindings/openssl/__init__.py
+++ b/cryptography/hazmat/bindings/openssl/__init__.py
@@ -10,3 +10,5 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/cryptography/hazmat/bindings/openssl/aes.py b/cryptography/hazmat/bindings/openssl/aes.py
index 95ed527..17c154c 100644
--- a/cryptography/hazmat/bindings/openssl/aes.py
+++ b/cryptography/hazmat/bindings/openssl/aes.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/aes.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/asn1.py b/cryptography/hazmat/bindings/openssl/asn1.py
index aeaf316..d908b19 100644
--- a/cryptography/hazmat/bindings/openssl/asn1.py
+++ b/cryptography/hazmat/bindings/openssl/asn1.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/asn1.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/bignum.py b/cryptography/hazmat/bindings/openssl/bignum.py
index e843099..a40397d 100644
--- a/cryptography/hazmat/bindings/openssl/bignum.py
+++ b/cryptography/hazmat/bindings/openssl/bignum.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/bn.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/bio.py b/cryptography/hazmat/bindings/openssl/bio.py
index 2817268..0c521b4 100644
--- a/cryptography/hazmat/bindings/openssl/bio.py
+++ b/cryptography/hazmat/bindings/openssl/bio.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/bio.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/conf.py b/cryptography/hazmat/bindings/openssl/conf.py
index 6d818cf..dda35e8 100644
--- a/cryptography/hazmat/bindings/openssl/conf.py
+++ b/cryptography/hazmat/bindings/openssl/conf.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/conf.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/crypto.py b/cryptography/hazmat/bindings/openssl/crypto.py
index 81d13b7..99e1a61 100644
--- a/cryptography/hazmat/bindings/openssl/crypto.py
+++ b/cryptography/hazmat/bindings/openssl/crypto.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/crypto.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/dh.py b/cryptography/hazmat/bindings/openssl/dh.py
index ecc62e9..1791a67 100644
--- a/cryptography/hazmat/bindings/openssl/dh.py
+++ b/cryptography/hazmat/bindings/openssl/dh.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/dh.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/dsa.py b/cryptography/hazmat/bindings/openssl/dsa.py
index 664296d..40d3b8e 100644
--- a/cryptography/hazmat/bindings/openssl/dsa.py
+++ b/cryptography/hazmat/bindings/openssl/dsa.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/dsa.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/ec.py b/cryptography/hazmat/bindings/openssl/ec.py
index 9d6f7cb..2617fe2 100644
--- a/cryptography/hazmat/bindings/openssl/ec.py
+++ b/cryptography/hazmat/bindings/openssl/ec.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #ifndef OPENSSL_NO_EC
 #include <openssl/ec.h>
diff --git a/cryptography/hazmat/bindings/openssl/engine.py b/cryptography/hazmat/bindings/openssl/engine.py
index 77118e8..364232e 100644
--- a/cryptography/hazmat/bindings/openssl/engine.py
+++ b/cryptography/hazmat/bindings/openssl/engine.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/engine.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/err.py b/cryptography/hazmat/bindings/openssl/err.py
index f21d98b..806d0ea 100644
--- a/cryptography/hazmat/bindings/openssl/err.py
+++ b/cryptography/hazmat/bindings/openssl/err.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/err.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/evp.py b/cryptography/hazmat/bindings/openssl/evp.py
index 77128c4..ad4b568 100644
--- a/cryptography/hazmat/bindings/openssl/evp.py
+++ b/cryptography/hazmat/bindings/openssl/evp.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/evp.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/hmac.py b/cryptography/hazmat/bindings/openssl/hmac.py
index 4b81c9d..6a64b92 100644
--- a/cryptography/hazmat/bindings/openssl/hmac.py
+++ b/cryptography/hazmat/bindings/openssl/hmac.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/hmac.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/nid.py b/cryptography/hazmat/bindings/openssl/nid.py
index a772d37..ea6fd4d 100644
--- a/cryptography/hazmat/bindings/openssl/nid.py
+++ b/cryptography/hazmat/bindings/openssl/nid.py
@@ -11,9 +11,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = ""
 
 TYPES = """
+static const int Cryptography_HAS_ECDSA_SHA2_NIDS;
+
 static const int NID_undef;
 static const int NID_dsa;
 static const int NID_dsaWithSHA;
@@ -189,6 +193,23 @@
 """
 
 CUSTOMIZATIONS = """
+// OpenSSL 0.9.8g+
+#if OPENSSL_VERSION_NUMBER >= 0x0090807fL
+static const long Cryptography_HAS_ECDSA_SHA2_NIDS = 1;
+#else
+static const long Cryptography_HAS_ECDSA_SHA2_NIDS = 0;
+static const int NID_ecdsa_with_SHA224 = 0;
+static const int NID_ecdsa_with_SHA256 = 0;
+static const int NID_ecdsa_with_SHA384 = 0;
+static const int NID_ecdsa_with_SHA512 = 0;
+#endif
 """
 
-CONDITIONAL_NAMES = {}
+CONDITIONAL_NAMES = {
+    "Cryptography_HAS_ECDSA_SHA2_NIDS": [
+        "NID_ecdsa_with_SHA224",
+        "NID_ecdsa_with_SHA256",
+        "NID_ecdsa_with_SHA384",
+        "NID_ecdsa_with_SHA512",
+    ],
+}
diff --git a/cryptography/hazmat/bindings/openssl/objects.py b/cryptography/hazmat/bindings/openssl/objects.py
index 0abc42d..557c015 100644
--- a/cryptography/hazmat/bindings/openssl/objects.py
+++ b/cryptography/hazmat/bindings/openssl/objects.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/objects.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/opensslv.py b/cryptography/hazmat/bindings/openssl/opensslv.py
index 397f4ca..e4aa621 100644
--- a/cryptography/hazmat/bindings/openssl/opensslv.py
+++ b/cryptography/hazmat/bindings/openssl/opensslv.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/opensslv.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/osrandom_engine.py b/cryptography/hazmat/bindings/openssl/osrandom_engine.py
index 0903a4b..462997c 100644
--- a/cryptography/hazmat/bindings/openssl/osrandom_engine.py
+++ b/cryptography/hazmat/bindings/openssl/osrandom_engine.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #ifdef _WIN32
 #include <Wincrypt.h>
diff --git a/cryptography/hazmat/bindings/openssl/pem.py b/cryptography/hazmat/bindings/openssl/pem.py
index 942cba3..e42fc6f 100644
--- a/cryptography/hazmat/bindings/openssl/pem.py
+++ b/cryptography/hazmat/bindings/openssl/pem.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/pem.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/pkcs12.py b/cryptography/hazmat/bindings/openssl/pkcs12.py
index bd01e75..a8f106f 100644
--- a/cryptography/hazmat/bindings/openssl/pkcs12.py
+++ b/cryptography/hazmat/bindings/openssl/pkcs12.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/pkcs12.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/pkcs7.py b/cryptography/hazmat/bindings/openssl/pkcs7.py
index 43f9540..1343e56 100644
--- a/cryptography/hazmat/bindings/openssl/pkcs7.py
+++ b/cryptography/hazmat/bindings/openssl/pkcs7.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/pkcs7.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/rand.py b/cryptography/hazmat/bindings/openssl/rand.py
index 0e645fb..7b1be9d 100644
--- a/cryptography/hazmat/bindings/openssl/rand.py
+++ b/cryptography/hazmat/bindings/openssl/rand.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/rand.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/rsa.py b/cryptography/hazmat/bindings/openssl/rsa.py
index f895cd0..c635610 100644
--- a/cryptography/hazmat/bindings/openssl/rsa.py
+++ b/cryptography/hazmat/bindings/openssl/rsa.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/rsa.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/ssl.py b/cryptography/hazmat/bindings/openssl/ssl.py
index 25bef49..362e24e 100644
--- a/cryptography/hazmat/bindings/openssl/ssl.py
+++ b/cryptography/hazmat/bindings/openssl/ssl.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/ssl.h>
 """
diff --git a/cryptography/hazmat/bindings/openssl/x509.py b/cryptography/hazmat/bindings/openssl/x509.py
index 95c88b3..e800d27 100644
--- a/cryptography/hazmat/bindings/openssl/x509.py
+++ b/cryptography/hazmat/bindings/openssl/x509.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/ssl.h>
 
@@ -120,8 +122,6 @@
 int X509_REQ_sign(X509_REQ *, EVP_PKEY *, const EVP_MD *);
 int X509_REQ_verify(X509_REQ *, EVP_PKEY *);
 EVP_PKEY *X509_REQ_get_pubkey(X509_REQ *);
-int X509_REQ_add_extensions(X509_REQ *, X509_EXTENSIONS *);
-X509_EXTENSIONS *X509_REQ_get_extensions(X509_REQ *);
 int X509_REQ_print_ex(BIO *, X509_REQ *, unsigned long, unsigned long);
 
 int X509V3_EXT_print(BIO *, X509_EXTENSION *, unsigned long, int);
@@ -208,9 +208,18 @@
 /* These aren't macros these arguments are all const X on openssl > 1.0.x */
 int X509_CRL_set_lastUpdate(X509_CRL *, ASN1_TIME *);
 int X509_CRL_set_nextUpdate(X509_CRL *, ASN1_TIME *);
+
+/* these use STACK_OF(X509_EXTENSION) in 0.9.8e. Once we drop support for
+   RHEL/CentOS 5 we should move these back to FUNCTIONS. */
+int X509_REQ_add_extensions(X509_REQ *, X509_EXTENSIONS *);
+X509_EXTENSIONS *X509_REQ_get_extensions(X509_REQ *);
 """
 
 CUSTOMIZATIONS = """
+// OpenSSL 0.9.8e does not have this definition
+#if OPENSSL_VERSION_NUMBER <= 0x0090805fL
+typedef STACK_OF(X509_EXTENSION) X509_EXTENSIONS;
+#endif
 """
 
 CONDITIONAL_NAMES = {}
diff --git a/cryptography/hazmat/bindings/openssl/x509name.py b/cryptography/hazmat/bindings/openssl/x509name.py
index bf627d6..50abee2 100644
--- a/cryptography/hazmat/bindings/openssl/x509name.py
+++ b/cryptography/hazmat/bindings/openssl/x509name.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/x509.h>
 
diff --git a/cryptography/hazmat/bindings/openssl/x509v3.py b/cryptography/hazmat/bindings/openssl/x509v3.py
index 6d2d236..02ec250 100644
--- a/cryptography/hazmat/bindings/openssl/x509v3.py
+++ b/cryptography/hazmat/bindings/openssl/x509v3.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 INCLUDES = """
 #include <openssl/x509v3.h>
 """
diff --git a/cryptography/hazmat/primitives/__init__.py b/cryptography/hazmat/primitives/__init__.py
index e69de29..2f42057 100644
--- a/cryptography/hazmat/primitives/__init__.py
+++ b/cryptography/hazmat/primitives/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/cryptography/hazmat/primitives/asymmetric/__init__.py b/cryptography/hazmat/primitives/asymmetric/__init__.py
index e69de29..2f42057 100644
--- a/cryptography/hazmat/primitives/asymmetric/__init__.py
+++ b/cryptography/hazmat/primitives/asymmetric/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/cryptography/hazmat/primitives/kdf/__init__.py b/cryptography/hazmat/primitives/kdf/__init__.py
index e69de29..2f42057 100644
--- a/cryptography/hazmat/primitives/kdf/__init__.py
+++ b/cryptography/hazmat/primitives/kdf/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/cryptography/hazmat/primitives/kdf/hkdf.py b/cryptography/hazmat/primitives/kdf/hkdf.py
index af15b64..1a46441 100644
--- a/cryptography/hazmat/primitives/kdf/hkdf.py
+++ b/cryptography/hazmat/primitives/kdf/hkdf.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import six
 
 from cryptography import utils
diff --git a/cryptography/hazmat/primitives/padding.py b/cryptography/hazmat/primitives/padding.py
index 1717262..bf634a6 100644
--- a/cryptography/hazmat/primitives/padding.py
+++ b/cryptography/hazmat/primitives/padding.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import cffi
 
 import six
diff --git a/cryptography/hazmat/primitives/twofactor/__init__.py b/cryptography/hazmat/primitives/twofactor/__init__.py
index e69de29..2f42057 100644
--- a/cryptography/hazmat/primitives/twofactor/__init__.py
+++ b/cryptography/hazmat/primitives/twofactor/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/docs/conf.py b/docs/conf.py
index 3486fb3..9b73a5b 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,4 +1,18 @@
 # -*- coding: utf-8 -*-
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 #
 # Cryptography documentation build configuration file, created by
 # sphinx-quickstart on Tue Aug  6 19:19:14 2013.
@@ -11,6 +25,8 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
+from __future__ import absolute_import, division, print_function
+
 import os
 import sys
 
diff --git a/docs/cryptography-docs.py b/docs/cryptography-docs.py
index 0252d69..e4e9296 100644
--- a/docs/cryptography-docs.py
+++ b/docs/cryptography-docs.py
@@ -1,3 +1,18 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
 from docutils import nodes
 
 from sphinx.util.compat import Directive, make_admonition
diff --git a/docs/development/custom-vectors/cast5/generate_cast5.py b/docs/development/custom-vectors/cast5/generate_cast5.py
index 32ef3b4..9dd241c 100644
--- a/docs/development/custom-vectors/cast5/generate_cast5.py
+++ b/docs/development/custom-vectors/cast5/generate_cast5.py
@@ -1,3 +1,18 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
 import binascii
 
 from cryptography.hazmat.backends import default_backend
diff --git a/docs/hazmat/backends/commoncrypto.rst b/docs/hazmat/backends/commoncrypto.rst
index 16a6133..d31391d 100644
--- a/docs/hazmat/backends/commoncrypto.rst
+++ b/docs/hazmat/backends/commoncrypto.rst
@@ -3,7 +3,8 @@
 CommonCrypto Backend
 ====================
 
-The `CommonCrypto`_ C library provided by Apple on OS X and iOS.
+The `CommonCrypto`_ C library provided by Apple on OS X and iOS. The CommonCrypto
+backend is only supported on OS X versions 10.8 and above.
 
 .. currentmodule:: cryptography.hazmat.backends.commoncrypto.backend
 
diff --git a/setup.py b/setup.py
index 238ee9b..7f7ba9e 100644
--- a/setup.py
+++ b/setup.py
@@ -10,6 +10,9 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
 import os
 import sys
 from distutils.command.build import build
diff --git a/tests/__init__.py b/tests/__init__.py
index e69de29..2f42057 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/tests/conftest.py b/tests/conftest.py
index 64982ef..0069f2c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,3 +1,18 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 from cryptography.hazmat.backends import _ALL_BACKENDS
diff --git a/tests/hazmat/__init__.py b/tests/hazmat/__init__.py
index e69de29..2f42057 100644
--- a/tests/hazmat/__init__.py
+++ b/tests/hazmat/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/tests/hazmat/backends/__init__.py b/tests/hazmat/backends/__init__.py
index e69de29..2f42057 100644
--- a/tests/hazmat/backends/__init__.py
+++ b/tests/hazmat/backends/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/tests/hazmat/backends/test_commoncrypto.py b/tests/hazmat/backends/test_commoncrypto.py
index 7feb0c7..1062b2b 100644
--- a/tests/hazmat/backends/test_commoncrypto.py
+++ b/tests/hazmat/backends/test_commoncrypto.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 from cryptography import utils
diff --git a/tests/hazmat/backends/test_multibackend.py b/tests/hazmat/backends/test_multibackend.py
index 87ef044..31fb0a2 100644
--- a/tests/hazmat/backends/test_multibackend.py
+++ b/tests/hazmat/backends/test_multibackend.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 from cryptography import utils
diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index c679218..599d153 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 from cryptography import utils
diff --git a/tests/hazmat/bindings/test_commoncrypto.py b/tests/hazmat/bindings/test_commoncrypto.py
index db3d1b7..0332674 100644
--- a/tests/hazmat/bindings/test_commoncrypto.py
+++ b/tests/hazmat/bindings/test_commoncrypto.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 from cryptography.hazmat.bindings.commoncrypto.binding import Binding
diff --git a/tests/hazmat/bindings/test_openssl.py b/tests/hazmat/bindings/test_openssl.py
index c476390..acab22b 100644
--- a/tests/hazmat/bindings/test_openssl.py
+++ b/tests/hazmat/bindings/test_openssl.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 from cryptography.hazmat.bindings.openssl.binding import Binding
diff --git a/tests/hazmat/primitives/__init__.py b/tests/hazmat/primitives/__init__.py
index e69de29..2f42057 100644
--- a/tests/hazmat/primitives/__init__.py
+++ b/tests/hazmat/primitives/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/tests/hazmat/primitives/test_padding.py b/tests/hazmat/primitives/test_padding.py
index 6a2b624..932cef1 100644
--- a/tests/hazmat/primitives/test_padding.py
+++ b/tests/hazmat/primitives/test_padding.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 import six
diff --git a/tests/hazmat/primitives/twofactor/__init__.py b/tests/hazmat/primitives/twofactor/__init__.py
index e69de29..2f42057 100644
--- a/tests/hazmat/primitives/twofactor/__init__.py
+++ b/tests/hazmat/primitives/twofactor/__init__.py
@@ -0,0 +1,14 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
diff --git a/tests/hazmat/primitives/twofactor/test_hotp.py b/tests/hazmat/primitives/twofactor/test_hotp.py
index 0f8c4a5..bc907c9 100644
--- a/tests/hazmat/primitives/twofactor/test_hotp.py
+++ b/tests/hazmat/primitives/twofactor/test_hotp.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import os
 
 import pytest
diff --git a/tests/hazmat/primitives/twofactor/test_totp.py b/tests/hazmat/primitives/twofactor/test_totp.py
index a4a108b..f3bddb8 100644
--- a/tests/hazmat/primitives/twofactor/test_totp.py
+++ b/tests/hazmat/primitives/twofactor/test_totp.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import pytest
 
 from cryptography.exceptions import InvalidToken
diff --git a/tests/hazmat/primitives/utils.py b/tests/hazmat/primitives/utils.py
index 5a8dc3a..f0a0031 100644
--- a/tests/hazmat/primitives/utils.py
+++ b/tests/hazmat/primitives/utils.py
@@ -1,3 +1,18 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
 import binascii
 import os
 
diff --git a/tests/test_fernet.py b/tests/test_fernet.py
index bd4d90a..36e8729 100644
--- a/tests/test_fernet.py
+++ b/tests/test_fernet.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import base64
 import calendar
 import json
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 622a665..352085a 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import os
 import textwrap
 
diff --git a/tests/utils.py b/tests/utils.py
index 0d9567f..519edb4 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -11,6 +11,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import, division, print_function
+
 import collections
 import os