diff --git a/.travis.yml b/.travis.yml
index a7b13e7f7f15..8350ebcac619 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -25,19 +25,6 @@ env:
     - TOX_ENV=pep8
     - TOX_ENV=py3pep8
 
-matrix:
-    allow_failures:
-        - env: TOX_ENV=py26 OPENSSL=0.9.8
-        - env: TOX_ENV=py27 OPENSSL=0.9.8
-        - env: TOX_ENV=py32 OPENSSL=0.9.8
-        - env: TOX_ENV=py33 OPENSSL=0.9.8
-        - env: TOX_ENV=pypy OPENSSL=0.9.8
-        - env: TOX_ENV=py26 CC=clang OPENSSL=0.9.8
-        - env: TOX_ENV=py27 CC=clang OPENSSL=0.9.8
-        - env: TOX_ENV=py32 CC=clang OPENSSL=0.9.8
-        - env: TOX_ENV=py33 CC=clang OPENSSL=0.9.8
-        - env: TOX_ENV=pypy CC=clang OPENSSL=0.9.8
-
 install:
     - "sudo add-apt-repository \"deb http://archive.ubuntu.com/ubuntu/ lucid main\""
     - sudo add-apt-repository -y ppa:pypy/ppa
@@ -47,11 +34,14 @@ install:
     # This is required because we need to get rid of the Travis installed PyPy
     # or it'll take precedence over the PPA installed one.
     - "[[ ${TOX_ENV} == pypy ]] && sudo rm -rf /usr/local/pypy/bin || true"
-    - pip install tox
+    - pip install tox coveralls
 
 script:
     - tox -e $TOX_ENV
 
+after_success:
+    - coveralls
+
 notifications:
     irc:
         channels:
diff --git a/README.rst b/README.rst
index c9baddea35cb..def2e1fc8f6d 100644
--- a/README.rst
+++ b/README.rst
@@ -2,13 +2,17 @@ Cryptography
 ============
 
 .. image:: https://travis-ci.org/pyca/cryptography.png?branch=master
-   :target: https://travis-ci.org/pyca/cryptography
+    :target: https://travis-ci.org/pyca/cryptography
+
+.. image:: https://coveralls.io/repos/pyca/cryptography/badge.png?branch=master
+    :target: https://coveralls.io/r/pyca/cryptography?branch=master
+
 
 ``cryptography`` is a package designed to expose cryptographic recipes and
 primitives to Python developers.
 
 It is currently in early development and isn't recommended for general usage
-yet. It targets Python 2.6-2.7, Python 3.2+, as well as PyPy.
+yet. It targets Python 2.6-2.7, Python 3.2+, and PyPy.
 
 You can find more information in the `documentation`_.
 
diff --git a/cryptography/hazmat/bindings/openssl/asn1.py b/cryptography/hazmat/bindings/openssl/asn1.py
index 5bd72e9ad7c7..719a523c01e2 100644
--- a/cryptography/hazmat/bindings/openssl/asn1.py
+++ b/cryptography/hazmat/bindings/openssl/asn1.py
@@ -119,3 +119,6 @@
 
 BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *, BIGNUM *);
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/backend.py b/cryptography/hazmat/bindings/openssl/backend.py
index ea1073b9180a..69ffde16638c 100644
--- a/cryptography/hazmat/bindings/openssl/backend.py
+++ b/cryptography/hazmat/bindings/openssl/backend.py
@@ -74,6 +74,7 @@ def _ensure_ffi_initialized(cls):
         includes = []
         functions = []
         macros = []
+        customizations = []
         for name in cls._modules:
             module_name = "cryptography.hazmat.bindings.openssl." + name
             __import__(module_name)
@@ -84,6 +85,7 @@ def _ensure_ffi_initialized(cls):
             macros.append(module.MACROS)
             functions.append(module.FUNCTIONS)
             includes.append(module.INCLUDES)
+            customizations.append(module.CUSTOMIZATIONS)
 
         # loop over the functions & macros after declaring all the types
         # so we can set interdependent types in different files and still
@@ -102,7 +104,7 @@ def _ensure_ffi_initialized(cls):
         #   int foo(int);
         #   int foo(short);
         lib = ffi.verify(
-            source="\n".join(includes + functions),
+            source="\n".join(includes + functions + customizations),
             libraries=["crypto", "ssl"],
         )
 
@@ -315,19 +317,20 @@ def create_ctx(self, key, hash_cls):
         evp_md = self._backend.lib.EVP_get_digestbyname(
             hash_cls.name.encode('ascii'))
         assert evp_md != self._backend.ffi.NULL
-        res = self._backend.lib.HMAC_Init_ex(ctx, key, len(key), evp_md,
-                                             self._backend.ffi.NULL)
+        res = self._backend.lib.Cryptography_HMAC_Init_ex(
+            ctx, key, len(key), evp_md, self._backend.ffi.NULL
+        )
         assert res != 0
         return ctx
 
     def update_ctx(self, ctx, data):
-        res = self._backend.lib.HMAC_Update(ctx, data, len(data))
+        res = self._backend.lib.Cryptography_HMAC_Update(ctx, data, len(data))
         assert res != 0
 
     def finalize_ctx(self, ctx, digest_size):
         buf = self._backend.ffi.new("unsigned char[]", digest_size)
         buflen = self._backend.ffi.new("unsigned int *", digest_size)
-        res = self._backend.lib.HMAC_Final(ctx, buf, buflen)
+        res = self._backend.lib.Cryptography_HMAC_Final(ctx, buf, buflen)
         assert res != 0
         self._backend.lib.HMAC_CTX_cleanup(ctx)
         return self._backend.ffi.buffer(buf)[:digest_size]
@@ -337,7 +340,7 @@ def copy_ctx(self, ctx):
         self._backend.lib.HMAC_CTX_init(copied_ctx)
         copied_ctx = self._backend.ffi.gc(copied_ctx,
                                           self._backend.lib.HMAC_CTX_cleanup)
-        res = self._backend.lib.HMAC_CTX_copy(copied_ctx, ctx)
+        res = self._backend.lib.Cryptography_HMAC_CTX_copy(copied_ctx, ctx)
         assert res != 0
         return copied_ctx
 
diff --git a/cryptography/hazmat/bindings/openssl/bignum.py b/cryptography/hazmat/bindings/openssl/bignum.py
index 72d467c3c2dd..fcfadff177d8 100644
--- a/cryptography/hazmat/bindings/openssl/bignum.py
+++ b/cryptography/hazmat/bindings/openssl/bignum.py
@@ -32,3 +32,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/bio.py b/cryptography/hazmat/bindings/openssl/bio.py
index 88be788f0a8a..c23dd0d8710b 100644
--- a/cryptography/hazmat/bindings/openssl/bio.py
+++ b/cryptography/hazmat/bindings/openssl/bio.py
@@ -168,3 +168,6 @@
 #define BIO_TYPE_BASE64 ...
 #define BIO_TYPE_FILTER ...
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/conf.py b/cryptography/hazmat/bindings/openssl/conf.py
index 85c7a210d5bb..4846252c78d9 100644
--- a/cryptography/hazmat/bindings/openssl/conf.py
+++ b/cryptography/hazmat/bindings/openssl/conf.py
@@ -24,3 +24,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/crypto.py b/cryptography/hazmat/bindings/openssl/crypto.py
index 501fb5a11016..773d9b14bf2c 100644
--- a/cryptography/hazmat/bindings/openssl/crypto.py
+++ b/cryptography/hazmat/bindings/openssl/crypto.py
@@ -35,3 +35,6 @@
 #define CRYPTO_MEM_CHECK_ENABLE ...
 #define CRYPTO_MEM_CHECK_DISABLE ...
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/dh.py b/cryptography/hazmat/bindings/openssl/dh.py
index ac130054e809..b8fbf3681930 100644
--- a/cryptography/hazmat/bindings/openssl/dh.py
+++ b/cryptography/hazmat/bindings/openssl/dh.py
@@ -26,3 +26,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/dsa.py b/cryptography/hazmat/bindings/openssl/dsa.py
index 2fa67b87b2b9..e6c369a6ecfb 100644
--- a/cryptography/hazmat/bindings/openssl/dsa.py
+++ b/cryptography/hazmat/bindings/openssl/dsa.py
@@ -28,3 +28,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/engine.py b/cryptography/hazmat/bindings/openssl/engine.py
index b3ec31253446..b76befce2895 100644
--- a/cryptography/hazmat/bindings/openssl/engine.py
+++ b/cryptography/hazmat/bindings/openssl/engine.py
@@ -50,3 +50,6 @@
 #define ENGINE_METHOD_ALL ...
 #define ENGINE_METHOD_NONE ...
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/err.py b/cryptography/hazmat/bindings/openssl/err.py
index 39ae315c0916..6a36dee0e106 100644
--- a/cryptography/hazmat/bindings/openssl/err.py
+++ b/cryptography/hazmat/bindings/openssl/err.py
@@ -57,3 +57,6 @@
 int ERR_GET_REASON(unsigned long);
 int ERR_FATAL_ERROR(unsigned long);
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/evp.py b/cryptography/hazmat/bindings/openssl/evp.py
index 4d0fb7fcfd3a..da54f89da639 100644
--- a/cryptography/hazmat/bindings/openssl/evp.py
+++ b/cryptography/hazmat/bindings/openssl/evp.py
@@ -29,9 +29,9 @@
 } EVP_PKEY;
 static const int EVP_PKEY_RSA;
 static const int EVP_PKEY_DSA;
-static const int EVP_CTRL_GCM_SET_IVLEN;
-static const int EVP_CTRL_GCM_GET_TAG;
-static const int EVP_CTRL_GCM_SET_TAG;
+static const int Cryptography_EVP_CTRL_GCM_SET_IVLEN;
+static const int Cryptography_EVP_CTRL_GCM_GET_TAG;
+static const int Cryptography_EVP_CTRL_GCM_SET_TAG;
 """
 
 FUNCTIONS = """
@@ -95,3 +95,15 @@
 int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *);
 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *, int, int, void *);
 """
+
+CUSTOMIZATIONS = """
+#ifdef EVP_CTRL_GCM_SET_TAG
+const int Cryptography_EVP_CTRL_GCM_GET_TAG = EVP_CTRL_GCM_GET_TAG;
+const int Cryptography_EVP_CTRL_GCM_SET_TAG = EVP_CTRL_GCM_SET_TAG;
+const int Cryptography_EVP_CTRL_GCM_SET_IVLEN = EVP_CTRL_GCM_SET_IVLEN;
+#else
+const int Cryptography_EVP_CTRL_GCM_GET_TAG = -1;
+const int Cryptography_EVP_CTRL_GCM_SET_TAG = -1;
+const int Cryptography_EVP_CTRL_GCM_SET_IVLEN = -1;
+#endif
+"""
diff --git a/cryptography/hazmat/bindings/openssl/hmac.py b/cryptography/hazmat/bindings/openssl/hmac.py
index e97ac35e5ce7..10e671418cd2 100644
--- a/cryptography/hazmat/bindings/openssl/hmac.py
+++ b/cryptography/hazmat/bindings/openssl/hmac.py
@@ -22,11 +22,69 @@
 FUNCTIONS = """
 void HMAC_CTX_init(HMAC_CTX *);
 void HMAC_CTX_cleanup(HMAC_CTX *);
-int HMAC_Init_ex(HMAC_CTX *, const void *, int, const EVP_MD *, ENGINE *);
-int HMAC_Update(HMAC_CTX *, const unsigned char *, size_t);
-int HMAC_Final(HMAC_CTX *, unsigned char *, unsigned int *);
-int HMAC_CTX_copy(HMAC_CTX *, HMAC_CTX *);
+
+int Cryptography_HMAC_Init_ex(HMAC_CTX *, const void *, int, const EVP_MD *,
+                              ENGINE *);
+int Cryptography_HMAC_Update(HMAC_CTX *, const unsigned char *, size_t);
+int Cryptography_HMAC_Final(HMAC_CTX *, unsigned char *, unsigned int *);
+int Cryptography_HMAC_CTX_copy(HMAC_CTX *, HMAC_CTX *);
 """
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+int Cryptography_HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int key_len,
+                              const EVP_MD *md, ENGINE *impl) {
+#if OPENSSL_VERSION_NUMBER >= 0x010000000
+    return HMAC_Init_ex(ctx, key, key_len, md, impl);
+#else
+    HMAC_Init_ex(ctx, key, key_len, md, impl);
+    return 1;
+#endif
+}
+
+int Cryptography_HMAC_Update(HMAC_CTX *ctx, const unsigned char *data,
+                             size_t data_len) {
+#if OPENSSL_VERSION_NUMBER >= 0x010000000
+    return HMAC_Update(ctx, data, data_len);
+#else
+    HMAC_Update(ctx, data, data_len);
+    return 1;
+#endif
+}
+
+int Cryptography_HMAC_Final(HMAC_CTX *ctx, unsigned char *digest,
+    unsigned int *digest_len) {
+#if OPENSSL_VERSION_NUMBER >= 0x010000000
+    return HMAC_Final(ctx, digest, digest_len);
+#else
+    HMAC_Final(ctx, digest, digest_len);
+    return 1;
+#endif
+}
+
+int Cryptography_HMAC_CTX_copy(HMAC_CTX *dst_ctx, HMAC_CTX *src_ctx) {
+#if OPENSSL_VERSION_NUMBER >= 0x010000000
+    return HMAC_CTX_copy(dst_ctx, src_ctx);
+#else
+    HMAC_CTX_init(dst_ctx);
+    if (!EVP_MD_CTX_copy_ex(&dst_ctx->i_ctx, &src_ctx->i_ctx)) {
+        goto err;
+    }
+    if (!EVP_MD_CTX_copy_ex(&dst_ctx->o_ctx, &src_ctx->o_ctx)) {
+        goto err;
+    }
+    if (!EVP_MD_CTX_copy_ex(&dst_ctx->md_ctx, &src_ctx->md_ctx)) {
+        goto err;
+    }
+    memcpy(dst_ctx->key, src_ctx->key, HMAC_MAX_MD_CBLOCK);
+    dst_ctx->key_length = src_ctx->key_length;
+    dst_ctx->md = src_ctx->md;
+    return 1;
+
+    err:
+        return 0;
+#endif
+}
+"""
diff --git a/cryptography/hazmat/bindings/openssl/nid.py b/cryptography/hazmat/bindings/openssl/nid.py
index 0f5b00030081..9816dde48b0b 100644
--- a/cryptography/hazmat/bindings/openssl/nid.py
+++ b/cryptography/hazmat/bindings/openssl/nid.py
@@ -39,6 +39,11 @@
 static const int NID_pbe_WithSHA1And3_Key_TripleDES_CBC;
 """
 
-FUNCTIONS = ""
+FUNCTIONS = """
+"""
+
+MACROS = """
+"""
 
-MACROS = ""
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/opensslv.py b/cryptography/hazmat/bindings/openssl/opensslv.py
index d1a1b3e69907..d463776c2418 100644
--- a/cryptography/hazmat/bindings/openssl/opensslv.py
+++ b/cryptography/hazmat/bindings/openssl/opensslv.py
@@ -24,3 +24,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/pem.py b/cryptography/hazmat/bindings/openssl/pem.py
index 8c8f736d6c44..00f0dc365fe1 100644
--- a/cryptography/hazmat/bindings/openssl/pem.py
+++ b/cryptography/hazmat/bindings/openssl/pem.py
@@ -41,4 +41,8 @@
 DH *PEM_read_bio_DHparams(BIO *, DH **, pem_password_cb *, void *);
 """
 
-MACROS = ""
+MACROS = """
+"""
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/pkcs12.py b/cryptography/hazmat/bindings/openssl/pkcs12.py
index 5c002b9389dd..d91d100f0525 100644
--- a/cryptography/hazmat/bindings/openssl/pkcs12.py
+++ b/cryptography/hazmat/bindings/openssl/pkcs12.py
@@ -32,3 +32,6 @@
 PKCS12 *PKCS12_create(char *, char *, EVP_PKEY *, X509 *,
                       struct stack_st_X509 *, int, int, int, int, int);
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/pkcs7.py b/cryptography/hazmat/bindings/openssl/pkcs7.py
index 752bfa002595..60ea3c5238ca 100644
--- a/cryptography/hazmat/bindings/openssl/pkcs7.py
+++ b/cryptography/hazmat/bindings/openssl/pkcs7.py
@@ -32,3 +32,6 @@
 int PKCS7_type_is_signedAndEnveloped(PKCS7 *);
 int PKCS7_type_is_data(PKCS7 *);
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/rand.py b/cryptography/hazmat/bindings/openssl/rand.py
index e4f6be23596a..848ee05a1ab1 100644
--- a/cryptography/hazmat/bindings/openssl/rand.py
+++ b/cryptography/hazmat/bindings/openssl/rand.py
@@ -35,3 +35,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/rsa.py b/cryptography/hazmat/bindings/openssl/rsa.py
index c8bf1cc01f40..21ed5d6710bf 100644
--- a/cryptography/hazmat/bindings/openssl/rsa.py
+++ b/cryptography/hazmat/bindings/openssl/rsa.py
@@ -29,3 +29,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/ssl.py b/cryptography/hazmat/bindings/openssl/ssl.py
index 8aca86e48d5f..58a64f0b9ac2 100644
--- a/cryptography/hazmat/bindings/openssl/ssl.py
+++ b/cryptography/hazmat/bindings/openssl/ssl.py
@@ -24,3 +24,6 @@
 
 MACROS = """
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/x509.py b/cryptography/hazmat/bindings/openssl/x509.py
index 9a51a6d011b8..b2ee672e33ac 100644
--- a/cryptography/hazmat/bindings/openssl/x509.py
+++ b/cryptography/hazmat/bindings/openssl/x509.py
@@ -185,3 +185,6 @@
 int X509_CRL_set_lastUpdate(X509_CRL *, const ASN1_TIME *);
 int X509_CRL_set_nextUpdate(X509_CRL *, const ASN1_TIME *);
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/x509name.py b/cryptography/hazmat/bindings/openssl/x509name.py
index bd7abe2d10e2..896f0ae410ed 100644
--- a/cryptography/hazmat/bindings/openssl/x509name.py
+++ b/cryptography/hazmat/bindings/openssl/x509name.py
@@ -46,3 +46,6 @@
 X509_NAME *sk_X509_NAME_value(struct stack_st_X509_NAME *, int);
 void sk_X509_NAME_free(struct stack_st_X509_NAME *);
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/cryptography/hazmat/bindings/openssl/x509v3.py b/cryptography/hazmat/bindings/openssl/x509v3.py
index 413bde5f228a..bc26236c19aa 100644
--- a/cryptography/hazmat/bindings/openssl/x509v3.py
+++ b/cryptography/hazmat/bindings/openssl/x509v3.py
@@ -92,3 +92,6 @@
 const X509V3_EXT_METHOD *X509V3_EXT_get(X509_EXTENSION *);
 const X509V3_EXT_METHOD *X509V3_EXT_get_nid(int);
 """
+
+CUSTOMIZATIONS = """
+"""
diff --git a/tox.ini b/tox.ini
index c0a9738f2086..dab22a6df573 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,7 @@ deps =
     pretend
 commands =
     coverage run --source=cryptography/,tests/ -m pytest
-    coverage report -m --fail-under 100
+    coverage report -m
 
 [testenv:docs]
 deps = sphinx