diff --git a/coreapi/chat.c b/coreapi/chat.c
index e25eecb25..3f9d6692c 100644
--- a/coreapi/chat.c
+++ b/coreapi/chat.c
@@ -264,6 +264,10 @@ LinphoneChatRoom *linphone_core_get_chat_room_from_uri(LinphoneCore *lc, const c
 	return _linphone_core_get_or_create_chat_room(lc, to);
 }
 
+bool_t linphone_chat_room_lime_enabled(LinphoneChatRoom *cr) {
+	return linphone_core_lime_enabled(cr->lc) != LinphoneLimeDisabled/*&& TODO: check that cr->peer_url has a verified token */;
+}
+
 static void linphone_chat_room_delete_composing_idle_timer(LinphoneChatRoom *cr) {
 	if (cr->composing_idle_timer) {
 		if (cr->lc && cr->lc->sal)
@@ -377,7 +381,7 @@ void _linphone_chat_room_send_message(LinphoneChatRoom *cr, LinphoneChatMessage
 			char *peer_uri = linphone_address_as_string_uri_only(linphone_chat_room_get_peer_address(cr));
 			const char *content_type;
 
-			if (linphone_core_lime_enabled(cr->lc)) {
+			if (linphone_chat_room_lime_enabled(cr)) {
 				/* ref the msg or it may be destroyed by callback if the encryption failed */
 				if (msg->content_type && strcmp(msg->content_type, "application/vnd.gsma.rcs-ft-http+xml") == 0) {
 					/* it's a file transfer, content type shall be set to
diff --git a/coreapi/chat_file_transfer.c b/coreapi/chat_file_transfer.c
index 4dc39ec07..e4c55f152 100644
--- a/coreapi/chat_file_transfer.c
+++ b/coreapi/chat_file_transfer.c
@@ -172,7 +172,8 @@ static void linphone_chat_message_process_response_from_post_file(void *data,
 			belle_sip_body_handler_t *first_part_bh;
 
 			/* shall we encrypt the file */
-			if (linphone_core_lime_for_file_sharing_enabled(msg->chat_room->lc)) {
+			if (linphone_chat_room_lime_enabled(msg->chat_room) &&
+			 linphone_core_lime_for_file_sharing_enabled(msg->chat_room->lc)) {
 				char keyBuffer
 					[FILE_TRANSFER_KEY_SIZE]; /* temporary storage of generated key: 192 bits of key + 64 bits of
 												 initial vector */
diff --git a/coreapi/linphonecore.c b/coreapi/linphonecore.c
index 375ad5a56..a39f28447 100644
--- a/coreapi/linphonecore.c
+++ b/coreapi/linphonecore.c
@@ -1856,18 +1856,22 @@ bool_t linphone_core_get_guess_hostname(LinphoneCore *lc){
 	return lc->sip_conf.guess_hostname;
 }
 
-void linphone_core_enable_lime(LinphoneCore *lc, bool_t val){
+void linphone_core_enable_lime(LinphoneCore *lc, LinphoneLimeState val){
 	if (linphone_core_ready(lc)){
 		lp_config_set_int(lc->config,"sip","lime",val);
 	}
 }
 
-bool_t linphone_core_lime_enabled(const LinphoneCore *lc){
-	return (lp_config_get_int(lc->config,"sip", "lime", FALSE) && lime_is_available());
+LinphoneLimeState linphone_core_lime_enabled(const LinphoneCore *lc){
+	return lime_is_available() ? lp_config_get_int(lc->config,"sip", "lime", LinphoneLimeDisabled) : LinphoneLimeDisabled;
 }
 
-bool_t linphone_core_lime_for_file_sharing_enabled(const LinphoneCore *lc){
-	return linphone_core_lime_enabled(lc) && (lp_config_get_int(lc->config,"sip", "lime_for_file_sharing", TRUE) && lime_is_available());
+LinphoneLimeState linphone_core_lime_for_file_sharing_enabled(const LinphoneCore *lc){
+	LinphoneLimeState s = linphone_core_lime_enabled(lc);
+	if (s != LinphoneLimeDisabled) {
+		s = lp_config_get_int(lc->config,"sip", "lime_for_file_sharing", LinphoneLimeMandatory);
+	}
+	return s;
 }
 
 LinphoneAddress *linphone_core_get_primary_contact_parsed(LinphoneCore *lc){
diff --git a/coreapi/linphonecore.h b/coreapi/linphonecore.h
index 42d326353..6494848fe 100644
--- a/coreapi/linphonecore.h
+++ b/coreapi/linphonecore.h
@@ -1241,6 +1241,12 @@ typedef enum _LinphoneChatMessageState {
 	LinphoneChatMessageStateFileTransferDone /**< File transfer has been completed successfully. */
 } LinphoneChatMessageState;
 
+typedef enum _LinphoneLimeState {
+	LinphoneLimeDisabled, /**< Lime is not used at all */
+	LinphoneLimeMandatory, /**< Lime is always used */
+	LinphoneLimePreferred, /**< Lime is used only if we already shared a secret with remote */
+} LinphoneLimeState;
+
 /**
  * Call back used to notify message delivery status
  * @param msg #LinphoneChatMessage object
@@ -2566,8 +2572,8 @@ LINPHONE_PUBLIC bool_t linphone_core_get_guess_hostname(LinphoneCore *lc);
  * Tells to LinphoneCore to use Linphone Instant Messaging encryption
  *
  */
-LINPHONE_PUBLIC void linphone_core_enable_lime(LinphoneCore *lc, bool_t val);
-LINPHONE_PUBLIC bool_t linphone_core_lime_enabled(const LinphoneCore *lc);
+LINPHONE_PUBLIC void linphone_core_enable_lime(LinphoneCore *lc, LinphoneLimeState val);
+LINPHONE_PUBLIC LinphoneLimeState linphone_core_lime_enabled(const LinphoneCore *lc);
 
 LINPHONE_PUBLIC	bool_t linphone_core_ipv6_enabled(LinphoneCore *lc);
 LINPHONE_PUBLIC	void linphone_core_enable_ipv6(LinphoneCore *lc, bool_t val);
diff --git a/coreapi/private.h b/coreapi/private.h
index a041c8126..7c9bfbb12 100644
--- a/coreapi/private.h
+++ b/coreapi/private.h
@@ -153,16 +153,16 @@ struct _LinphoneCallParams{
 	bool_t has_video;
 	bool_t avpf_enabled; /* RTCP feedback messages are enabled */
 	bool_t implicit_rtcp_fb;
-	
+
 	bool_t real_early_media; /*send real media even during early media (for outgoing calls)*/
 	bool_t in_conference; /*in conference mode */
 	bool_t low_bandwidth;
 	bool_t no_user_consent;/*when set to TRUE an UPDATE request will be used instead of reINVITE*/
-	
+
 	uint16_t avpf_rr_interval; /*in milliseconds*/
 	bool_t internal_call_update; /*use mark that call update was requested internally (might be by ice) - unused for the moment*/
 	bool_t video_multicast_enabled;
-	
+
 	bool_t audio_multicast_enabled;
 	bool_t realtimetext_enabled;
 	bool_t update_call_when_ice_completed;
@@ -356,7 +356,7 @@ struct _LinphoneCall{
 
 	bool_t paused_by_app;
 	bool_t broken; /*set to TRUE when the call is in broken state due to network disconnection or transport */
-	
+
 	LinphoneConference *conf_ref; /**> Point on the associated conference if this call is part of a conference. NULL instead. */
 };
 
@@ -399,7 +399,7 @@ void linphone_proxy_config_stop_refreshing(LinphoneProxyConfig *obj);
 void linphone_proxy_config_write_all_to_config_file(LinphoneCore *lc);
 void _linphone_proxy_config_release(LinphoneProxyConfig *cfg);
 void _linphone_proxy_config_unpublish(LinphoneProxyConfig *obj);
-	
+
 /*
  * returns service route as defined in as defined by rfc3608, might be a list instead of just one.
  * Can be NULL
@@ -574,6 +574,7 @@ int linphone_chat_room_upload_file(LinphoneChatMessage *msg);
 void _linphone_chat_room_send_message(LinphoneChatRoom *cr, LinphoneChatMessage *msg);
 LinphoneChatMessageCbs *linphone_chat_message_cbs_new(void);
 LinphoneChatRoom *_linphone_core_create_chat_room_from_call(LinphoneCall *call);
+bool_t linphone_chat_room_lime_enabled(LinphoneChatRoom *cr);
 /**/
 
 struct _LinphoneProxyConfig
@@ -930,12 +931,12 @@ struct _LinphoneCore
 	bool_t auto_net_state_mon;
 	bool_t sip_network_reachable;
 	bool_t media_network_reachable;
-	
+
 	bool_t network_reachable_to_be_notified; /*set to true when state must be notified in next iterate*/
 	bool_t use_preview_window;
 	bool_t network_last_status;
 	bool_t ringstream_autorelease;
-	
+
 	bool_t vtables_running;
 	bool_t send_call_stats_periodical_updates;
 	bool_t forced_ice_relay;
@@ -1440,14 +1441,14 @@ LINPHONE_PUBLIC void _linphone_core_add_listener(LinphoneCore *lc, LinphoneCoreV
 LINPHONE_PUBLIC MSWebCam *linphone_call_get_video_device(const LinphoneCall *call);
 MSWebCam *get_nowebcam_device(MSFactory *f);
 #endif
-bool_t linphone_core_lime_for_file_sharing_enabled(const LinphoneCore *lc);
+LinphoneLimeState linphone_core_lime_for_file_sharing_enabled(const LinphoneCore *lc);
 
 BELLE_SIP_DECLARE_VPTR(LinphoneTunnelConfig);
 
 int linphone_core_get_default_proxy_config_index(LinphoneCore *lc);
 
 char *linphone_presence_model_to_xml(LinphonePresenceModel *model) ;
-	
+
 #ifdef __cplusplus
 }
 #endif