Rename signed fields to signed portion
diff --git a/ndn-cpp/encoding/binary-xml-wire-format.cpp b/ndn-cpp/encoding/binary-xml-wire-format.cpp
index 55a6d77..930f89d 100644
--- a/ndn-cpp/encoding/binary-xml-wire-format.cpp
+++ b/ndn-cpp/encoding/binary-xml-wire-format.cpp
@@ -60,7 +60,7 @@
   interest.set(interestStruct);
 }
 
-Blob BinaryXmlWireFormat::encodeData(const Data& data, unsigned int *signedFieldsBeginOffset, unsigned int *signedFieldsEndOffset) 
+Blob BinaryXmlWireFormat::encodeData(const Data& data, unsigned int *signedPortionBeginOffset, unsigned int *signedPortionEndOffset) 
 {
   struct ndn_NameComponent nameComponents[100];
   struct ndn_NameComponent keyNameComponents[100];
@@ -72,14 +72,14 @@
 
   BinaryXmlEncoder encoder;
   ndn_Error error;
-  if ((error = ndn_encodeBinaryXmlData(&dataStruct, signedFieldsBeginOffset, signedFieldsEndOffset, &encoder)))
+  if ((error = ndn_encodeBinaryXmlData(&dataStruct, signedPortionBeginOffset, signedPortionEndOffset, &encoder)))
     throw std::runtime_error(ndn_getErrorString(error));
      
   return encoder.getOutput();
 }
 
 void BinaryXmlWireFormat::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)
 {
   struct ndn_NameComponent nameComponents[100];
   struct ndn_NameComponent keyNameComponents[100];
@@ -90,7 +90,7 @@
     
   BinaryXmlDecoder decoder(input, inputLength);  
   ndn_Error error;
-  if ((error = ndn_decodeBinaryXmlData(&dataStruct, signedFieldsBeginOffset, signedFieldsEndOffset, &decoder)))
+  if ((error = ndn_decodeBinaryXmlData(&dataStruct, signedPortionBeginOffset, signedPortionEndOffset, &decoder)))
     throw std::runtime_error(ndn_getErrorString(error));
 
   data.set(dataStruct);
diff --git a/ndn-cpp/encoding/binary-xml-wire-format.hpp b/ndn-cpp/encoding/binary-xml-wire-format.hpp
index 0f11aa4..ebb7412 100644
--- a/ndn-cpp/encoding/binary-xml-wire-format.hpp
+++ b/ndn-cpp/encoding/binary-xml-wire-format.hpp
@@ -35,29 +35,29 @@
   /**
    * Encode data with binary XML and return the encoding.
    * @param data The Data object to encode.
-   * @param signedFieldsBeginOffset Return the offset in the encoding of the beginning of the fields which are signed.
+   * @param signedPortionBeginOffset Return the offset in the encoding of the beginning of the signed portion.
    * If you are not encoding in order to sign, you can call encodeData(const Data& data) to ignore this returned value.
-   * @param signedFieldsEndOffset Return the offset in the encoding of the end of the fields which are signed.
+   * @param signedPortionEndOffset Return the offset in the encoding of the end of the signed portion.
    * If you are not encoding in order to sign, you can call encodeData(const Data& data) to ignore this returned value.
    * @return A Blob containing the encoding.
    */
   virtual Blob encodeData
-    (const Data& data, unsigned int *signedFieldsBeginOffset, unsigned int *signedFieldsEndOffset);
+    (const Data& data, unsigned int *signedPortionBeginOffset, unsigned int *signedPortionEndOffset);
   
   /**
    * Decode input as a data packet in binary XML and set the fields in the data object.
    * @param data The Data object whose fields are updated.
    * @param input A pointer to the input buffer to decode.
    * @param inputLength The number of bytes in input.
-   * @param signedFieldsBeginOffset Return the offset in the input buffer of the beginning of the fields which are signed.
+   * @param signedPortionBeginOffset Return the offset in the input buffer of the beginning of the signed portion.
    * If you are not decoding in order to verify, you can call 
    * decodeData(Data& data, const unsigned char *input, unsigned int inputLength) to ignore this returned value.
-   * @param signedFieldsEndOffset Return the offset in the input buffer of the end of the fields which are signed.
+   * @param signedPortionEndOffset Return the offset in the input buffer of the end of the signed portion.
    * If you are not decoding in order to verify, you can call 
    * decodeData(Data& data, const unsigned char *input, unsigned int inputLength) to ignore this returned value.
    */  
   virtual void 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);
 
   /**
    * Encode forwardingEntry in binary XML and return the encoding. 
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");
 }
diff --git a/ndn-cpp/encoding/wire-format.hpp b/ndn-cpp/encoding/wire-format.hpp
index e6a19f5..a892659 100644
--- a/ndn-cpp/encoding/wire-format.hpp
+++ b/ndn-cpp/encoding/wire-format.hpp
@@ -38,15 +38,15 @@
   /**
    * Encode data and return the encoding.  Your derived class should override.
    * @param data The Data object to encode.
-   * @param signedFieldsBeginOffset Return the offset in the encoding of the beginning of the fields which are signed.
+   * @param signedPortionBeginOffset Return the offset in the encoding of the beginning of the signed portion.
    * If you are not encoding in order to sign, you can call encodeData(const Data& data) to ignore this returned value.
-   * @param signedFieldsEndOffset Return the offset in the encoding of the end of the fields which are signed.
+   * @param signedPortionEndOffset Return the offset in the encoding of the end of the signed portion.
    * If you are not encoding in order to sign, you can call encodeData(const Data& data) to ignore this returned value.
    * @return A Blob containing the encoding.
    * @throw logic_error for unimplemented if the derived class does not override.
    */
   virtual Blob encodeData
-    (const Data& data, unsigned int *signedFieldsBeginOffset, unsigned int *signedFieldsEndOffset);
+    (const Data& data, unsigned int *signedPortionBeginOffset, unsigned int *signedPortionEndOffset);
 
   /**
    * Encode data and return the encoding.
@@ -65,16 +65,16 @@
    * @param data The Data object whose fields are updated.
    * @param input A pointer to the input buffer to decode.
    * @param inputLength The number of bytes in input.
-   * @param signedFieldsBeginOffset Return the offset in the input buffer of the beginning of the fields which are signed.
+   * @param signedPortionBeginOffset Return the offset in the input buffer of the beginning of the signed portion.
    * If you are not decoding in order to verify, you can call 
    * decodeData(Data& data, const unsigned char *input, unsigned int inputLength) to ignore this returned value.
-   * @param signedFieldsEndOffset Return the offset in the input buffer of the end of the fields which are signed.
+   * @param signedPortionEndOffset Return the offset in the input buffer of the end of the signed portion.
    * If you are not decoding in order to verify, you can call 
    * decodeData(Data& data, const unsigned char *input, unsigned int inputLength) to ignore this returned value.
    * @throw logic_error for unimplemented if the derived class does not override.
    */  
   virtual void 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);
 
   void decodeData(Data& data, const unsigned char *input, unsigned int inputLength)
   {