diff --git a/src/common/inc/string_utilities.h b/src/common/inc/string_utilities.h
index ed0ffe6c..e4625b15 100644
--- a/src/common/inc/string_utilities.h
+++ b/src/common/inc/string_utilities.h
@@ -79,7 +79,7 @@ StringUtils_createBufferFromHexString(char* hexString, uint8_t* buffer);
  * \brief test if string starts with prefix
  */
 LIB61850_INTERNAL bool
-StringUtils_startsWith(char* string, char* prefix);
+StringUtils_startsWith(const char* string, const char* prefix);
 
 LIB61850_INTERNAL bool
 StringUtils_endsWith(const char* str, const char* suffix);
diff --git a/src/common/string_utilities.c b/src/common/string_utilities.c
index cb121690..dc197009 100644
--- a/src/common/string_utilities.c
+++ b/src/common/string_utilities.c
@@ -230,7 +230,7 @@ StringUtils_createBufferFromHexString(char* hexString, uint8_t* buffer)
 }
 
 bool
-StringUtils_startsWith(char* string, char* prefix)
+StringUtils_startsWith(const char* string, const char* prefix)
 {
     int index = 0;