diff --git a/websocketpp/base64/base64.hpp b/websocketpp/base64/base64.hpp
index 2fed34228d..6c12ec19c8 100644
--- a/websocketpp/base64/base64.hpp
+++ b/websocketpp/base64/base64.hpp
@@ -50,10 +50,6 @@ static inline bool is_base64(unsigned char c) {
            (c >= 97 && c <= 122)); // a-z
 }
 
-inline std::string base64_encode(const std::string & data) {
-    return base64_encode(data.data(),data.size());
-}
-
 inline std::string base64_encode(unsigned char const* bytes_to_encode, unsigned 
     int in_len)
 {
@@ -104,6 +100,10 @@ inline std::string base64_encode(unsigned char const* bytes_to_encode, unsigned
   return ret;
 }
 
+inline std::string base64_encode(const std::string & data) {
+    return base64_encode(reinterpret_cast<const unsigned char *>(data.data()),data.size());
+}
+
 inline std::string base64_decode(std::string const& encoded_string) {
     size_t in_len = encoded_string.size();
     int i = 0;