diff --git a/src/line_info.h b/src/line_info.h
index e9618a7..92f7dc2 100644
--- a/src/line_info.h
+++ b/src/line_info.h
@@ -21,7 +21,7 @@
  */
 
 #ifndef _line_info_h
-#define line_info_h
+#define _line_info_h
 
 #include "windows.h"
 #include "toxic.h"
@@ -91,4 +91,4 @@ void line_info_init(struct history *hst);
 void line_info_onKey(ToxWindow *self, wint_t key);
 void line_info_onDraw(ToxWindow *self);
 
-#endif /* #define line_info_h */
+#endif /* #define _line_info_h */
diff --git a/src/prompt.c b/src/prompt.c
index a6e387d..20220ae 100644
--- a/src/prompt.c
+++ b/src/prompt.c
@@ -102,7 +102,7 @@ void prompt_update_connectionstatus(ToxWindow *prompt, bool is_connected)
 
 /* Adds friend request to pending friend requests.
    Returns request number on success, -1 if queue is full or other error. */
-static int add_friend_request(uint8_t *public_key)
+static int add_friend_request(const uint8_t *public_key)
 {
     if (num_frnd_requests >= MAX_FRIENDS_NUM)
         return -1;
@@ -403,10 +403,9 @@ static void prompt_onConnectionChange(ToxWindow *self, Tox *m, int32_t friendnum
     }
 }
 
-static void prompt_onFriendRequest(ToxWindow *self, Tox *m, uint8_t *key, uint8_t *data, uint16_t length)
+static void prompt_onFriendRequest(ToxWindow *self, Tox *m, const uint8_t *key, const uint8_t *data,
+                                   uint16_t length)
 {
-    data[length] = '\0';
-
     ChatContext *ctx = self->chatwin;
 
     uint8_t timefrmt[TIME_STR_SIZE];
diff --git a/src/toxic.h b/src/toxic.h
index 46d4588..87b7f82 100644
--- a/src/toxic.h
+++ b/src/toxic.h
@@ -62,7 +62,7 @@ enum {
    Uncomment if necessary */
 /* #define URXVT_FIX */
 
-void on_request(Tox *m, uint8_t *public_key, uint8_t *data, uint16_t length, void *userdata);
+void on_request(Tox *m, const uint8_t *public_key, const uint8_t *data, uint16_t length, void *userdata);
 void on_connectionchange(Tox *m, int32_t friendnumber, uint8_t status, void *userdata);
 void on_message(Tox *m, int32_t friendnumber, uint8_t *string, uint16_t length, void *userdata);
 void on_action(Tox *m, int32_t friendnumber, uint8_t *string, uint16_t length, void *userdata);
diff --git a/src/windows.c b/src/windows.c
index ef14525..e73910c 100644
--- a/src/windows.c
+++ b/src/windows.c
@@ -44,7 +44,7 @@ extern ToxWindow *prompt;
 static int num_active_windows;
 
 /* CALLBACKS START */
-void on_request(Tox *m, uint8_t *public_key, uint8_t *data, uint16_t length, void *userdata)
+void on_request(Tox *m, const uint8_t *public_key, const uint8_t *data, uint16_t length, void *userdata)
 {
     int i;
 
diff --git a/src/windows.h b/src/windows.h
index 99aa74f..9e3fc7b 100644
--- a/src/windows.h
+++ b/src/windows.h
@@ -76,7 +76,7 @@ struct ToxWindow {
     void(*onKey)(ToxWindow *, Tox *, wint_t, bool);
     void(*onDraw)(ToxWindow *, Tox *);
     void(*onInit)(ToxWindow *, Tox *);
-    void(*onFriendRequest)(ToxWindow *, Tox *, uint8_t *, uint8_t *, uint16_t);
+    void(*onFriendRequest)(ToxWindow *, Tox *, const uint8_t *, const uint8_t *, uint16_t);
     void(*onFriendAdded)(ToxWindow *, Tox *, int32_t, bool);
     void(*onConnectionChange)(ToxWindow *, Tox *, int32_t, uint8_t);
     void(*onMessage)(ToxWindow *, Tox *, int32_t, uint8_t *, uint16_t);