diff --git a/toxcore/Messenger.c b/toxcore/Messenger.c
index b07b6012..37a7a252 100644
--- a/toxcore/Messenger.c
+++ b/toxcore/Messenger.c
@@ -959,7 +959,7 @@ static int get_chat_num(Messenger *m, Group_Chat *chat)
     return -1;
 }
 
-static void group_message_function(Group_Chat *chat, int peer_number, uint8_t *message, uint16_t length, void *userdata)
+static void group_message_function(Group_Chat *chat, int peer_number, const uint8_t *message, uint16_t length, void *userdata)
 {
     Messenger *m = userdata;
     int i = get_chat_num(m, chat);
@@ -975,7 +975,7 @@ static void group_message_function(Group_Chat *chat, int peer_number, uint8_t *m
         (*m->group_message)(m, i, peer_number, message_terminated, length, m->group_message_userdata);
 }
 
-static void group_action_function(Group_Chat *chat, int peer_number, uint8_t *action, uint16_t length, void *userdata)
+static void group_action_function(Group_Chat *chat, int peer_number, const uint8_t *action, uint16_t length, void *userdata)
 {
     Messenger *m = userdata;
     int i = get_chat_num(m, chat);
diff --git a/toxcore/group_chats.c b/toxcore/group_chats.c
index 85928436..882b3f42 100644
--- a/toxcore/group_chats.c
+++ b/toxcore/group_chats.c
@@ -65,7 +65,7 @@ typedef struct {
  * TODO: make this more efficient.
  */
 
-static int peer_in_chat(Group_Chat *chat, uint8_t *client_id)
+static int peer_in_chat(const Group_Chat *chat, const uint8_t *client_id)
 {
     uint32_t i;
 
@@ -82,7 +82,7 @@ static int peer_in_chat(Group_Chat *chat, uint8_t *client_id)
  *  return 1 if client_id1 is closer.
  *  return 2 if client_id2 is closer.
  */
-static int id_closest_groupchats(uint8_t *id, uint8_t *id1, uint8_t *id2)
+static int id_closest_groupchats(const uint8_t *id, const uint8_t *id1, const uint8_t *id2)
 {
     size_t   i;
     uint8_t distance1, distance2;
@@ -110,7 +110,7 @@ static int id_closest_groupchats(uint8_t *id, uint8_t *id1, uint8_t *id2)
  * Return -1 if the peer is in the closelist.
  */
 
-static int peer_okping(Group_Chat *chat, uint8_t *client_id)
+static int peer_okping(const Group_Chat *chat, const uint8_t *client_id)
 {
     uint32_t i, j = 0;
 
@@ -143,7 +143,7 @@ static int peer_okping(Group_Chat *chat, uint8_t *client_id)
  * Return 0 if success.
  * Return -1 if peer was not put in list/updated.
  */
-static int add_closepeer(Group_Chat *chat, uint8_t *client_id, IP_Port ip_port)
+static int add_closepeer(Group_Chat *chat, const uint8_t *client_id, IP_Port ip_port)
 {
     uint32_t i;
 
@@ -175,7 +175,7 @@ static int add_closepeer(Group_Chat *chat, uint8_t *client_id, IP_Port ip_port)
     return -1;
 }
 
-static int send_groupchatpacket(Group_Chat *chat, IP_Port ip_port, uint8_t *public_key, uint8_t *data, uint32_t length,
+static int send_groupchatpacket(const Group_Chat *chat, IP_Port ip_port, const uint8_t *public_key, const uint8_t *data, uint32_t length,
                                 uint8_t request_id)
 {
     if (id_equal(chat->self_public_key, public_key))
@@ -200,7 +200,7 @@ static int send_groupchatpacket(Group_Chat *chat, IP_Port ip_port, uint8_t *publ
  *
  * return the number of peers the packet was sent to.
  */
-static uint8_t sendto_allpeers(Group_Chat *chat, uint8_t *data, uint16_t length, uint8_t request_id)
+static uint8_t sendto_allpeers(const Group_Chat *chat, const uint8_t *data, uint16_t length, uint8_t request_id)
 {
     uint16_t sent = 0;
     uint32_t i;
@@ -224,7 +224,7 @@ static uint8_t sendto_allpeers(Group_Chat *chat, uint8_t *data, uint16_t length,
  * return peernum if success or peer already in chat.
  * return -1 if error.
  */
-static int addpeer(Group_Chat *chat, uint8_t *client_id)
+static int addpeer(Group_Chat *chat, const uint8_t *client_id)
 {
     int peernum = peer_in_chat(chat, client_id);
 
@@ -319,7 +319,7 @@ static int delpeer(Group_Chat *chat, int peernum)
  * return length of name if success
  * return -1 if failure
  */
-int group_peername(Group_Chat *chat, int peernum, uint8_t *name)
+int group_peername(const Group_Chat *chat, int peernum, uint8_t *name)
 {
     if ((uint32_t)peernum >= chat->numpeers)
         return -1;
@@ -334,7 +334,7 @@ int group_peername(Group_Chat *chat, int peernum, uint8_t *name)
     return chat->group[peernum].nick_len;
 }
 
-static void setnick(Group_Chat *chat, int peernum, uint8_t *contents, uint16_t contents_len)
+static void setnick(Group_Chat *chat, int peernum, const uint8_t *contents, uint16_t contents_len)
 {
     if (contents_len > MAX_NICK_BYTES || contents_len == 0)
         return;
@@ -355,7 +355,7 @@ static void setnick(Group_Chat *chat, int peernum, uint8_t *contents, uint16_t c
 /* TODO: move this to global section */
 #define GROUP_PING_TIMEOUT 5
 
-static int send_getnodes(Group_Chat *chat, IP_Port ip_port, int peernum)
+static int send_getnodes(const Group_Chat *chat, IP_Port ip_port, int peernum)
 {
     if ((uint32_t)peernum >= chat->numpeers)
         return -1;
@@ -382,7 +382,7 @@ static int send_getnodes(Group_Chat *chat, IP_Port ip_port, int peernum)
                                 CRYPTO_PACKET_GROUP_CHAT_GET_NODES);
 }
 
-static int send_sendnodes(Group_Chat *chat, IP_Port ip_port, int peernum, uint64_t pingid)
+static int send_sendnodes(const Group_Chat *chat, IP_Port ip_port, int peernum, uint64_t pingid)
 {
     if ((uint32_t)peernum >= chat->numpeers)
         return -1;
@@ -404,7 +404,7 @@ static int send_sendnodes(Group_Chat *chat, IP_Port ip_port, int peernum, uint64
                                 sizeof(contents.pingid) + sizeof(groupchat_nodes) * j, CRYPTO_PACKET_GROUP_CHAT_SEND_NODES);
 }
 
-static int handle_getnodes(Group_Chat *chat, IP_Port source, int peernum, uint8_t *data, uint32_t len)
+static int handle_getnodes(const Group_Chat *chat, IP_Port source, int peernum, const uint8_t *data, uint32_t len)
 {
     if (len != sizeof(getnodes_data))
         return 1;
@@ -422,7 +422,7 @@ static int handle_getnodes(Group_Chat *chat, IP_Port source, int peernum, uint8_
     return 0;
 }
 
-static int handle_sendnodes(Group_Chat *chat, IP_Port source, int peernum, uint8_t *data, uint32_t len)
+static int handle_sendnodes(Group_Chat *chat, IP_Port source, int peernum, const uint8_t *data, uint32_t len)
 {
     if ((uint32_t)peernum >= chat->numpeers)
         return 1;
@@ -487,7 +487,7 @@ static int handle_sendnodes(Group_Chat *chat, IP_Port source, int peernum, uint8
 #define GROUP_DATA_MIN_SIZE (crypto_box_PUBLICKEYBYTES + sizeof(uint32_t) + 1)
 static void send_names_new_peer(Group_Chat *chat);
 
-static int handle_data(Group_Chat *chat, uint8_t *data, uint32_t len)
+static int handle_data(Group_Chat *chat, const uint8_t *data, uint32_t len)
 {
     if (len < GROUP_DATA_MIN_SIZE)
         return 1;
@@ -526,7 +526,7 @@ static int handle_data(Group_Chat *chat, uint8_t *data, uint32_t len)
     chat->group[peernum].last_message_number = message_num;
 
     int handled = 1;
-    uint8_t *contents = data + GROUP_DATA_MIN_SIZE;
+    const uint8_t *contents = data + GROUP_DATA_MIN_SIZE;
     uint16_t contents_len = len - GROUP_DATA_MIN_SIZE;
 
     switch (data[crypto_box_PUBLICKEYBYTES + sizeof(message_num)]) {
@@ -585,7 +585,7 @@ static int handle_data(Group_Chat *chat, uint8_t *data, uint32_t len)
     return 1;
 }
 
-static uint8_t send_data(Group_Chat *chat, uint8_t *data, uint32_t len, uint8_t message_id)
+static uint8_t send_data(Group_Chat *chat, const uint8_t *data, uint32_t len, uint8_t message_id)
 {
     if (len + GROUP_DATA_MIN_SIZE > MAX_CRYPTO_REQUEST_SIZE) /*NOTE: not the real maximum len.*/
         return 1;
@@ -614,7 +614,7 @@ static uint8_t send_data(Group_Chat *chat, uint8_t *data, uint32_t len, uint8_t
  * return 1 if error.
  */
 
-int handle_groupchatpacket(Group_Chat *chat, IP_Port source, uint8_t *packet, uint32_t length)
+int handle_groupchatpacket(Group_Chat *chat, IP_Port source, const uint8_t *packet, uint32_t length)
 {
     if (length > MAX_CRYPTO_REQUEST_SIZE)
         return 1;
@@ -652,12 +652,12 @@ int handle_groupchatpacket(Group_Chat *chat, IP_Port source, uint8_t *packet, ui
     return 1;
 }
 
-uint32_t group_sendmessage(Group_Chat *chat, uint8_t *message, uint32_t length)
+uint32_t group_sendmessage(Group_Chat *chat, const uint8_t *message, uint32_t length)
 {
     return send_data(chat, message, length, GROUP_CHAT_CHAT_MESSAGE); //TODO: better return values?
 }
 
-uint32_t group_sendaction(Group_Chat *chat, uint8_t *action, uint32_t length)
+uint32_t group_sendaction(Group_Chat *chat, const uint8_t *action, uint32_t length)
 {
     return send_data(chat, action, length, GROUP_CHAT_ACTION);
 }
@@ -686,20 +686,20 @@ int set_nick(Group_Chat *chat, const uint8_t *nick, uint16_t nick_len)
     return 0;
 }
 
-uint32_t group_newpeer(Group_Chat *chat, uint8_t *client_id)
+uint32_t group_newpeer(Group_Chat *chat, const uint8_t *client_id)
 {
     addpeer(chat, client_id);
     return send_data(chat, client_id, crypto_box_PUBLICKEYBYTES, GROUP_CHAT_NEW_PEER); //TODO: better return values?
 }
 
-void callback_groupmessage(Group_Chat *chat, void (*function)(Group_Chat *chat, int, uint8_t *, uint16_t, void *),
+void callback_groupmessage(Group_Chat *chat, void (*function)(Group_Chat *chat, int, const uint8_t *, uint16_t, void *),
                            void *userdata)
 {
     chat->group_message = function;
     chat->group_message_userdata = userdata;
 }
 
-void callback_groupaction(Group_Chat *chat, void (*function)(Group_Chat *chat, int, uint8_t *, uint16_t, void *),
+void callback_groupaction(Group_Chat *chat, void (*function)(Group_Chat *chat, int, const uint8_t *, uint16_t, void *),
                           void *userdata)
 {
     chat->group_action = function;
@@ -713,12 +713,12 @@ void callback_namelistchange(Group_Chat *chat, void (*function)(Group_Chat *chat
     chat->group_namelistchange_userdata = userdata;
 }
 
-uint32_t group_numpeers(Group_Chat *chat)
+uint32_t group_numpeers(const Group_Chat *chat)
 {
     return chat->numpeers;
 }
 
-uint32_t group_client_names(Group_Chat *chat, uint8_t names[][MAX_NICK_BYTES], uint16_t lengths[], uint16_t length)
+uint32_t group_client_names(const Group_Chat *chat, uint8_t names[][MAX_NICK_BYTES], uint16_t lengths[], uint16_t length)
 {
     uint32_t i;
 
@@ -833,12 +833,12 @@ void kill_groupchat(Group_Chat *chat)
     free(chat);
 }
 
-void chat_bootstrap(Group_Chat *chat, IP_Port ip_port, uint8_t *client_id)
+void chat_bootstrap(Group_Chat *chat, IP_Port ip_port, const uint8_t *client_id)
 {
     send_getnodes(chat, ip_port, addpeer(chat, client_id));
 }
 
-void chat_bootstrap_nonlazy(Group_Chat *chat, IP_Port ip_port, uint8_t *client_id)
+void chat_bootstrap_nonlazy(Group_Chat *chat, IP_Port ip_port, const uint8_t *client_id)
 {
     send_getnodes(chat, ip_port, addpeer(chat, client_id));
     add_closepeer(chat, client_id, ip_port);
diff --git a/toxcore/group_chats.h b/toxcore/group_chats.h
index 49b83c81..802d345b 100644
--- a/toxcore/group_chats.h
+++ b/toxcore/group_chats.h
@@ -62,9 +62,9 @@ typedef struct Group_Chat {
     uint32_t numpeers;
 
     uint32_t message_number;
-    void (*group_message)(struct Group_Chat *m, int, uint8_t *, uint16_t, void *);
+    void (*group_message)(struct Group_Chat *m, int, const uint8_t *, uint16_t, void *);
     void *group_message_userdata;
-    void (*group_action)(struct Group_Chat *m, int, uint8_t *, uint16_t, void *);
+    void (*group_action)(struct Group_Chat *m, int, const uint8_t *, uint16_t, void *);
     void *group_action_userdata;
     void (*peer_namelistchange)(struct Group_Chat *m, int peer, uint8_t change, void *);
     void *group_namelistchange_userdata;
@@ -91,14 +91,14 @@ typedef struct Group_Chat {
  * return length of name if success
  * return -1 if failure
  */
-int group_peername(Group_Chat *chat, int peernum, uint8_t *name);
+int group_peername(const Group_Chat *chat, int peernum, uint8_t *name);
 
 /*
  * Set callback function for chat messages.
  *
  * format of function is: function(Group_Chat *chat, peer number, message, message length, userdata)
  */
-void callback_groupmessage(Group_Chat *chat, void (*function)(Group_Chat *chat, int, uint8_t *, uint16_t, void *),
+void callback_groupmessage(Group_Chat *chat, void (*function)(Group_Chat *chat, int, const uint8_t *, uint16_t, void *),
                            void *userdata);
 
 /*
@@ -106,7 +106,7 @@ void callback_groupmessage(Group_Chat *chat, void (*function)(Group_Chat *chat,
  *
  * format of function is: function(Group_Chat *chat, peer number, action, action length, userdata)
  */
-void callback_groupaction(Group_Chat *chat, void (*function)(Group_Chat *chat, int, uint8_t *, uint16_t, void *),
+void callback_groupaction(Group_Chat *chat, void (*function)(Group_Chat *chat, int, const uint8_t *, uint16_t, void *),
                           void *userdata);
 
 /*
@@ -130,14 +130,14 @@ void callback_namelistchange(Group_Chat *chat, void (*function)(Group_Chat *chat
  *
  * returns the number of peers it has sent it to.
  */
-uint32_t group_sendmessage(Group_Chat *chat, uint8_t *message, uint32_t length);
+uint32_t group_sendmessage(Group_Chat *chat, const uint8_t *message, uint32_t length);
 
 /*
  * Send an action to the group.
  *
  * returns the number of peers it has sent it to.
  */
-uint32_t group_sendaction(Group_Chat *chat, uint8_t *action, uint32_t length);
+uint32_t group_sendaction(Group_Chat *chat, const uint8_t *action, uint32_t length);
 
 /*
  * Set our nick for this group.
@@ -150,7 +150,7 @@ int set_nick(Group_Chat *chat, const uint8_t *nick, uint16_t nick_len);
  * Tell everyone about a new peer (a person we are inviting for example.)
  *
  */
-uint32_t group_newpeer(Group_Chat *chat, uint8_t *client_id);
+uint32_t group_newpeer(Group_Chat *chat, const uint8_t *client_id);
 
 
 /* Create a new group chat.
@@ -164,7 +164,7 @@ Group_Chat *new_groupchat(Networking_Core *net);
 
 /* Return the number of peers in the group chat.
  */
-uint32_t group_numpeers(Group_Chat *chat);
+uint32_t group_numpeers(const Group_Chat *chat);
 
 /* List all the peers in the group chat.
  *
@@ -172,7 +172,7 @@ uint32_t group_numpeers(Group_Chat *chat);
  *
  * returns the number of peers.
  */
-uint32_t group_client_names(Group_Chat *chat, uint8_t names[][MAX_NICK_BYTES], uint16_t lengths[], uint16_t length);
+uint32_t group_client_names(const Group_Chat *chat, uint8_t names[][MAX_NICK_BYTES], uint16_t lengths[], uint16_t length);
 
 /* Kill a group chat
  *
@@ -188,11 +188,11 @@ void do_groupchat(Group_Chat *chat);
 /* if we receive a group chat packet we call this function so it can be handled.
     return 0 if packet is handled correctly.
     return 1 if it didn't handle the packet or if the packet was shit. */
-int handle_groupchatpacket(Group_Chat *chat, IP_Port source, uint8_t *packet, uint32_t length);
+int handle_groupchatpacket(Group_Chat *chat, IP_Port source, const uint8_t *packet, uint32_t length);
 
 
-void chat_bootstrap(Group_Chat *chat, IP_Port ip_port, uint8_t *client_id);
-void chat_bootstrap_nonlazy(Group_Chat *chat, IP_Port ip_port, uint8_t *client_id);
+void chat_bootstrap(Group_Chat *chat, IP_Port ip_port, const uint8_t *client_id);
+void chat_bootstrap_nonlazy(Group_Chat *chat, IP_Port ip_port, const uint8_t *client_id);
 
 
 #endif