signature: Small API fixes

Change-Id: I1718dd5bdf702151e8125801a8f1dfc23cb680e4
diff --git a/src/signature.hpp b/src/signature.hpp
index 7d4159c..362e172 100644
--- a/src/signature.hpp
+++ b/src/signature.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) 2013-2016 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -73,6 +73,15 @@
   }
 
   /**
+   * @brief Get SignatureInfo
+   */
+  const SignatureInfo&
+  getSignatureInfo() const
+  {
+    return m_info;
+  }
+
+  /**
    * @brief Set SignatureInfo from a block
    *
    * @throws tlv::Error if supplied block is not formatted correctly