diff --git a/tests/security/identity-fixture.cpp b/tests/security/identity-fixture.cpp
new file mode 100644
index 0000000..2cc7e4f
--- /dev/null
+++ b/tests/security/identity-fixture.cpp
@@ -0,0 +1,52 @@
+/**
+ * Copyright (C) 2013 Regents of the University of California.
+ * @author: Yingdi Yu <yingdi0@cs.ucla.edu>
+ * See COPYING for copyright and distribution information.
+ */
+
+#include "security/key-chain.hpp"
+#include <boost/test/unit_test.hpp>
+
+namespace ndn {
+
+// OSX KeyChain, when used on a headless server,
+// forbids usage of a private key if that key isn't created by the calling process.
+// Therefore, unit testing must create its own key pair.
+
+class IdentityFixture
+{
+public:
+  IdentityFixture()
+  {
+    // save the old default identity
+    m_oldDefaultIdentity = m_keyChain.getDefaultIdentity();
+
+    m_newIdentity.set("/ndn-cpp-dev-test-identity");
+    m_newIdentity.appendVersion();
+
+    // create the new identity and self-signed certificate
+    m_keyChain.createIdentity(m_newIdentity);
+
+    // set the new identity as default identity,
+    // and the corresponding certificate becomes the default certificate
+    m_keyChain.setDefaultIdentity(m_newIdentity);
+  }
+
+  ~IdentityFixture()
+  {
+    // recover the old default setting
+    m_keyChain.setDefaultIdentity(m_oldDefaultIdentity);
+
+    // remove the temporarily created identity and certificates
+    m_keyChain.deleteIdentity(m_newIdentity);
+  }
+
+private:
+  KeyChain m_keyChain;
+  Name m_oldDefaultIdentity;
+  Name m_newIdentity;
+};
+
+BOOST_GLOBAL_FIXTURE(IdentityFixture);
+
+} // namespace ndn