diff --git a/src/matchfile.c b/src/matchfile.c
index f2ec975f..7d124421 100644
--- a/src/matchfile.c
+++ b/src/matchfile.c
@@ -144,7 +144,7 @@ int          matchfile_release(matchfile_t *file) {
 }
 
 /* we are not const char *key because of avl_get_by_key()... */
-int          matchfile_match(matchfile_t *file, char *key) {
+int          matchfile_match(matchfile_t *file, const char *key) {
     void *result;
 
     if (!file)
@@ -159,7 +159,7 @@ int          matchfile_match(matchfile_t *file, char *key) {
     return avl_get_by_key(file->contents, (void*)key, &result) == 0 ? 1 : 0;
 }
 
-int          matchfile_match_allow_deny(matchfile_t *allow, matchfile_t *deny, char *key) {
+int          matchfile_match_allow_deny(matchfile_t *allow, matchfile_t *deny, const char *key) {
     if (!allow && !deny)
         return 1;
 
diff --git a/src/matchfile.h b/src/matchfile.h
index 72d32d9e..2e25f7eb 100644
--- a/src/matchfile.h
+++ b/src/matchfile.h
@@ -15,9 +15,9 @@ typedef struct matchfile_tag matchfile_t;
 matchfile_t *matchfile_new(const char *filename);
 int          matchfile_addref(matchfile_t *file);
 int          matchfile_release(matchfile_t *file);
-int          matchfile_match(matchfile_t *file, char *key);
+int          matchfile_match(matchfile_t *file, const char *key);
 
 /* returns 1 for allow or pass and 0 for deny */
-int          matchfile_match_allow_deny(matchfile_t *allow, matchfile_t *deny, char *key);
+int          matchfile_match_allow_deny(matchfile_t *allow, matchfile_t *deny, const char *key);
 
 #endif  /* __MATCHFILE_H__ */