diff --git a/acme/acme/crypto_util.py b/acme/acme/crypto_util.py
index 2b2133475..266f2c0c7 100644
--- a/acme/acme/crypto_util.py
+++ b/acme/acme/crypto_util.py
@@ -63,6 +63,8 @@ class SSLSocket(object):  # pylint: disable=too-few-public-methods
                          server_name)
             return
         new_context = OpenSSL.SSL.Context(self.method)
+        new_context.set_options(OpenSSL.SSL.OP_NO_SSLv2)
+        new_context.set_options(OpenSSL.SSL.OP_NO_SSLv3)
         new_context.use_privatekey(key)
         new_context.use_certificate(cert)
         connection.set_context(new_context)
@@ -86,6 +88,8 @@ class SSLSocket(object):  # pylint: disable=too-few-public-methods
         sock, addr = self.sock.accept()
 
         context = OpenSSL.SSL.Context(self.method)
+        context.set_options(OpenSSL.SSL.OP_NO_SSLv2)
+        context.set_options(OpenSSL.SSL.OP_NO_SSLv3)
         context.set_tlsext_servername_callback(self._pick_certificate_cb)
 
         ssl_sock = self.FakeConnection(OpenSSL.SSL.Connection(context, sock))
diff --git a/acme/acme/crypto_util_test.py b/acme/acme/crypto_util_test.py
index 75a908d4f..913b50164 100644
--- a/acme/acme/crypto_util_test.py
+++ b/acme/acme/crypto_util_test.py
@@ -19,8 +19,8 @@ class SSLSocketAndProbeSNITest(unittest.TestCase):
     """Tests for acme.crypto_util.SSLSocket/probe_sni."""
 
     def setUp(self):
-        self.cert = test_util.load_comparable_cert('cert.pem')
-        key = test_util.load_pyopenssl_private_key('rsa512_key.pem')
+        self.cert = test_util.load_comparable_cert('rsa2048_cert.pem')
+        key = test_util.load_pyopenssl_private_key('rsa2048_key.pem')
         # pylint: disable=protected-access
         certs = {b'foo': (key, self.cert.wrapped)}
 
diff --git a/acme/acme/standalone_test.py b/acme/acme/standalone_test.py
index 85cd9d11d..92a0b4272 100644
--- a/acme/acme/standalone_test.py
+++ b/acme/acme/standalone_test.py
@@ -33,8 +33,8 @@ class TLSSNI01ServerTest(unittest.TestCase):
 
     def setUp(self):
         self.certs = {b'localhost': (
-            test_util.load_pyopenssl_private_key('rsa512_key.pem'),
-            test_util.load_cert('cert.pem'),
+            test_util.load_pyopenssl_private_key('rsa2048_key.pem'),
+            test_util.load_cert('rsa2048_cert.pem'),
         )}
         from acme.standalone import TLSSNI01Server
         self.server = TLSSNI01Server(("", 0), certs=self.certs)
@@ -114,8 +114,9 @@ class TestSimpleTLSSNI01Server(unittest.TestCase):
         self.test_cwd = tempfile.mkdtemp()
         localhost_dir = os.path.join(self.test_cwd, 'localhost')
         os.makedirs(localhost_dir)
-        shutil.copy(test_util.vector_path('cert.pem'), localhost_dir)
-        shutil.copy(test_util.vector_path('rsa512_key.pem'),
+        shutil.copy(test_util.vector_path('rsa2048_cert.pem'),
+                    os.path.join(localhost_dir, 'cert.pem'))
+        shutil.copy(test_util.vector_path('rsa2048_key.pem'),
                     os.path.join(localhost_dir, 'key.pem'))
 
         from acme.standalone import simple_tls_sni_01_server
@@ -147,7 +148,8 @@ class TestSimpleTLSSNI01Server(unittest.TestCase):
                 time.sleep(1)  # wait until thread starts
             else:
                 self.assertEqual(jose.ComparableX509(cert),
-                                 test_util.load_comparable_cert('cert.pem'))
+                                 test_util.load_comparable_cert(
+                                     'rsa2048_cert.pem'))
                 break
 
 
diff --git a/acme/acme/testdata/rsa2048_cert.pem b/acme/acme/testdata/rsa2048_cert.pem
new file mode 100644
index 000000000..3944cd1db
--- /dev/null
+++ b/acme/acme/testdata/rsa2048_cert.pem
@@ -0,0 +1,22 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/acme/acme/testdata/rsa2048_key.pem b/acme/acme/testdata/rsa2048_key.pem
index 33efd3467..5847aed55 100644
--- a/acme/acme/testdata/rsa2048_key.pem
+++ b/acme/acme/testdata/rsa2048_key.pem
@@ -1,27 +1,28 @@
------BEGIN RSA PRIVATE KEY-----
-MIIEowIBAAKCAQEA8HwZMHeImB/iM8/n8CTCR4KeYQB2gLGO3v8xLms+PWH3Zbxc
-dVtEn25Y34scIh+iOuEXBcSBalBddLHKBGVN3nCfmpupoLm52xgRG44q9OWODpg4
-FSi4afqVw2agMx0RHi0v3GVcdpqB83UW42kK1ESZHUuq7mxLg8u3IMYZFm6Amsf+
-YQjBbDNn8NczJOFhsExP2EdM5ykgM1Om8aqTqqPMgPub68/r4Sym+BjLnvRq5Qtz
-h/jCfOBIIpAwg3lj7l8OyE3kkD3ALtuiuminNUqLHEkUaLq/Xiv8V8mvnrhG7h3Q
-+L1Xc707P0dz5YM5XxTMhmUE1cae/lQ0KbNrpwIDAQABAoIBAAiDXCDrGlrIRimv
-YnaN1pLRfOnSKl/D6VrbjdIm2b0yip9/W4aMBJHgRiUjt4s9s3CCJ1585lftIGHR
-KWWecHM/aWb/u7GE4Z9v6qsfDUY+GhlKKjIVjvGxfTu9lk446TI4R0l2DR/luFP2
-ASlrvoZlJ0ZyN0rZapLv0zvFx32Tukd+3rcMmXfHl7aRGMZG1YTKNmBJ4d9iJ6cP
-HG3fgSzLQMPLNO/20MzbXdREG5FNQtwaMuFnIcVbtMCvc/71lQQEfANMLCUweEed
-YWGOjgDeh+731nJsopel+2TSTgnf5VhcFrgChZZdqeKvP+HbXjTE2VkWo7BrzoM7
-xICYBwECgYEA/ZF/JOjZfwIMUdikv8vldJzRMdFryl4NJWnh4NeThNOEpUcpxnyK
-wyMnnQaGJa51u9EEnzl0sZ2h2ODjD6KFpz6fkWaVRq5SWalVPAoKZGaoPZV3IUOI
-8Tm0xkXho+A/FUUEcxCLME+3V9EdPfHaVRJOrbfDyxvNhsj4w9F0aAkCgYEA8sp7
-XTrolOknJGv4Qt1w6gcm5+cMtLaRfi8ZHPHujl2x9eWE8/s2818az7jc0Xr/G4HQ
-NeU+3Es4BblEckSHmhUZhx26cZgkLSIIDofEtaEc6u8CyWfxsWvn3l4T3kMdeSLC
-9UoLk59AH2tkMIh8vzV8LSisLJa341lMdgryQi8CgYAlJKr7PSCe+i3Tz2hSsAts
-iYwbQBIKErzaPihYRzvUuSc1DreP26535y5mUg5UdrnISVXj/Qaa/fw3SLn6EFSD
-qyi0o9I6CE8H00YpBU+AZYk/fCV3Oe1VaJ6SbKog1zhmZTXBpSq+aO7ybi9aY5MX
-4xajW8fSeMAifk3yYTwsAQKBgErcEcOCOVpItU/uloKPYpRWFjHktK83p46fmP+q
-vOJak1d9KExOBfhuN4caucNBSE1D7l3fzE0CSEjDgg41gRYKMW/Ow8DopybfWlqY
-lBdokNEDVvmgug35dmnC2h9q1DiYdkJJTV57+Lp3U1H/k28lX59Q7h1lb1eDHic7
-YszzAoGBAOx05dhOiYbzAJSTQu3oBHFn4mTYIqCcDO6cQrEJwPKAq7mAhT0yOk9N
-CrqRV/1aes665829cyTwcAZl6nqbzHv5XjX5+g6vmooCb4oCkq49rumHjoQdrX8D
-RR5b+Spkc1jo4rctCcExzSkgo+K5N3oBVYznecje7O7Z0/qiJE/8
------END RSA PRIVATE KEY-----
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----
diff --git a/acme/examples/standalone/localhost/cert.pem b/acme/examples/standalone/localhost/cert.pem
index 569366af9..1cca87af5 120000
--- a/acme/examples/standalone/localhost/cert.pem
+++ b/acme/examples/standalone/localhost/cert.pem
@@ -1 +1 @@
-../../../acme/testdata/cert.pem
\ No newline at end of file
+../../../acme/testdata/rsa2048_cert.pem
\ No newline at end of file
diff --git a/acme/examples/standalone/localhost/key.pem b/acme/examples/standalone/localhost/key.pem
index 870f4f876..ee3dd2847 120000
--- a/acme/examples/standalone/localhost/key.pem
+++ b/acme/examples/standalone/localhost/key.pem
@@ -1 +1 @@
-../../../acme/testdata/rsa512_key.pem
\ No newline at end of file
+../../../acme/testdata/rsa2048_key.pem
\ No newline at end of file