diff --git a/protocols/vnc/include/convert.h b/protocols/vnc/include/convert.h
index d6cf1258..8b373227 100644
--- a/protocols/vnc/include/convert.h
+++ b/protocols/vnc/include/convert.h
@@ -47,7 +47,7 @@
  * @return A newly allocated string that is the result of the conversion, or NULL
  *         if an error has occured.
  */
-char* convert (const char* from_charset, const char* to_charset, char* input);
+char* convert (const char* from_charset, const char* to_charset, const char* input);
 
 #endif
 
diff --git a/protocols/vnc/src/convert.c b/protocols/vnc/src/convert.c
index 55cd6daa..7becb34c 100644
--- a/protocols/vnc/src/convert.c
+++ b/protocols/vnc/src/convert.c
@@ -40,7 +40,7 @@
 #include <iconv.h>
 #include <errno.h>
 
-char* convert(const char* from_charset, const char* to_charset, char* input) {
+char* convert(const char* from_charset, const char* to_charset, const char* input) {
     size_t input_remaining;
     size_t output_remaining;
     size_t bytes_converted = 0;
@@ -58,7 +58,7 @@ char* convert(const char* from_charset, const char* to_charset, char* input) {
         return NULL;
  
     input_remaining = strlen(input);
-    input_buffer = input;
+    input_buffer = (char*) input;
  
     /* Start the output buffer the same size as the input buffer */
     output_length = input_remaining;