diff --git a/src/Serializer.cpp b/src/Serializer.cpp
index 8b67d3b65..016c6e2a6 100644
--- a/src/Serializer.cpp
+++ b/src/Serializer.cpp
@@ -305,7 +305,7 @@ uint256 Serializer::getSHA512Half(const unsigned char *data, int len)
 
 uint256 Serializer::getSHA512Half(const std::string& strData)
 {
-	return getSHA512Half(reinterpret_cast<const unsigned char*>(strData.c_str()), strData.size());
+	return getSHA512Half(reinterpret_cast<const unsigned char*>(strData.data()), strData.size());
 }
 
 uint256 Serializer::getPrefixHash(uint32 prefix, const unsigned char *data, int len)
@@ -367,7 +367,16 @@ int Serializer::addVL(const std::vector<unsigned char>& vector)
 int Serializer::addVL(const void *ptr, int len)
 {
 	int ret = addRaw(encodeVL(len));
-	if (len) addRaw(ptr, len);
+	if (len)
+		addRaw(ptr, len);
+	return ret;
+}
+
+int Serializer::addVL(const std::string& string)
+{
+	int ret = addRaw(string.size());
+	if (!string.empty())
+		addRaw(string.data(), string.size());
 	return ret;
 }
 
diff --git a/src/Serializer.h b/src/Serializer.h
index fc1f1df49..7b7b67fe2 100644
--- a/src/Serializer.h
+++ b/src/Serializer.h
@@ -44,6 +44,7 @@ public:
 	int addZeros(size_t uBytes);
 
 	int addVL(const std::vector<unsigned char> &vector);
+	int addVL(const std::string& string);
 	int addVL(const void *ptr, int len);
 	int addTaggedList(const std::list<TaggedListItem>&);
 	int addTaggedList(const std::vector<TaggedListItem>&);
@@ -87,7 +88,7 @@ public:
 	static uint256 getPrefixHash(uint32 prefix, const std::vector<unsigned char>& data)
 		{ return getPrefixHash(prefix, &(data.front()), data.size()); }
 	static uint256 getPrefixHash(uint32 prefix, const std::string& strData)
-		{ return getPrefixHash(prefix, reinterpret_cast<const unsigned char *>(strData.c_str()), strData.size()); }
+		{ return getPrefixHash(prefix, reinterpret_cast<const unsigned char *>(strData.data()), strData.size()); }
 
 	// totality functions
 	const std::vector<unsigned char>& peekData() const		{ return mData; }