diff --git a/src/encoding/tlv.cpp b/src/encoding/tlv.cpp
new file mode 100644
index 0000000..4de73a1
--- /dev/null
+++ b/src/encoding/tlv.cpp
@@ -0,0 +1,42 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2017 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#include "tlv.hpp"
+
+namespace ndn {
+namespace tlv {
+
+std::ostream&
+operator<<(std::ostream& os, const SignatureTypeValue& signatureType)
+{
+  switch (signatureType) {
+    case SignatureTypeValue::DigestSha256:
+      return os << "DigestSha256";
+    case SignatureTypeValue::SignatureSha256WithRsa:
+      return os << "SignatureSha256WithRsa";
+    case SignatureTypeValue::SignatureSha256WithEcdsa:
+      return os << "SignatureSha256WithEcdsa";
+  }
+  return os << "Unknown Signature Type";
+}
+
+} // namespace tlv
+} // namespace ndn
diff --git a/src/encoding/tlv.hpp b/src/encoding/tlv.hpp
index ad964e2..c9a6520 100644
--- a/src/encoding/tlv.hpp
+++ b/src/encoding/tlv.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2013-2015 Regents of the University of California.
+ * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -99,6 +99,9 @@
   SignatureSha256WithEcdsa = 3
 };
 
+std::ostream&
+operator<<(std::ostream& os, const SignatureTypeValue& signatureType);
+
 /** @brief TLV codes for SignatureInfo features
  *  @sa docs/tutorials/certificate-format.rst
  */