Rename signed fields to signed portion
diff --git a/ndn-cpp/encoding/wire-format.cpp b/ndn-cpp/encoding/wire-format.cpp
index 450f3e0..fc39a7b 100644
--- a/ndn-cpp/encoding/wire-format.cpp
+++ b/ndn-cpp/encoding/wire-format.cpp
@@ -36,12 +36,12 @@
   throw logic_error("unimplemented");
 }
 
-Blob WireFormat::encodeData(const Data& data, unsigned int *signedFieldsBeginOffset, unsigned int *signedFieldsEndOffset) 
+Blob WireFormat::encodeData(const Data& data, unsigned int *signedPortionBeginOffset, unsigned int *signedPortionEndOffset) 
 {
   throw logic_error("unimplemented");
 }
 void WireFormat::decodeData
-  (Data& data, const unsigned char *input, unsigned int inputLength, unsigned int *signedFieldsBeginOffset, unsigned int *signedFieldsEndOffset) 
+  (Data& data, const unsigned char *input, unsigned int inputLength, unsigned int *signedPortionBeginOffset, unsigned int *signedPortionEndOffset) 
 {
   throw logic_error("unimplemented");
 }