diff --git a/src/s1ap/handlers/attach_secmoderesp.c b/src/s1ap/handlers/attach_secmoderesp.c
new file mode 100644
index 0000000..0215075
--- /dev/null
+++ b/src/s1ap/handlers/attach_secmoderesp.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "err_codes.h"
+#include "options.h"
+#include "ipc_api.h"
+#include "main.h"
+#include "s1ap.h"
+#include "s1ap_config.h"
+#include "sctp_conn.h"
+#include "s1ap_structs.h"
+#include "s1ap_msg_codes.h"
+#include "msgType.h"
+
+
+extern int g_enb_fd;
+extern ipc_handle ipc_S1ap_Hndl;
+
+int
+s1_secmode_resp_handler(struct proto_IE *s1_sec_resp_ies)
+{
+	//TODO: use static instead of synamic for perf.
+	struct s1_incoming_msg_data_t secmode_resp= {0};
+
+	/*****Message structure***
+	*/
+	log_msg(LOG_INFO, "Parse s1ap sec mode complete message:--\n");
+
+	/*Validate all eNB info*/
+
+	/*Add eNB info to hash*/
+
+	/*Create Q structure for stage 1 to MME.
+	  contains init UE information.*/
+	secmode_resp.msg_type = sec_mode_complete;
+	
+	for(int i = 0; i < s1_sec_resp_ies->no_of_IEs; i++)
+    {
+        switch(s1_sec_resp_ies->data[i].IE_type)
+        {
+            case S1AP_IE_MME_UE_ID:
+                {
+	                secmode_resp.ue_idx = s1_sec_resp_ies->data[i].val.mme_ue_s1ap_id;
+                }break;
+            case S1AP_IE_NAS_PDU:
+                {
+                    if(s1_sec_resp_ies->data[i].val.nas.header.message_type != NAS_SEC_MODE_COMPLETE)
+                    {
+                        secmode_resp.msg_data.secmode_resp_Q_msg_m.status = S1AP_SECMODE_FAILED;//Error in authentication
+                    }
+                    else
+                    {
+                        secmode_resp.msg_data.secmode_resp_Q_msg_m.status = SUCCESS;
+                    }
+
+                }break;
+            default:
+                log_msg(LOG_WARNING,"Unhandled IE");
+        }
+    }
+
+	/*Copy xres from response, send to mme for verification*/
+	//...
+	//auth_res.res.len = a1_secmode_resp_ies[2].data.nas.authresp_len;
+	//memcpy(&(auth_res.res.val, s1_sec_resp_ies[2].data.nas.RES, authres.res.len);
+
+	secmode_resp.destInstAddr = htonl(mmeAppInstanceNum_c);
+	secmode_resp.srcInstAddr = htonl(s1apAppInstanceNum_c);
+	send_tipc_message(ipc_S1ap_Hndl, mmeAppInstanceNum_c, (char *)&secmode_resp, S1_READ_MSG_BUF_SIZE);
+
+	/*Send S1Setup response*/
+	log_msg(LOG_INFO, "Auth resp send to mme-app stage4.\n");
+
+	//TODO: free IEs
+	return SUCCESS;
+}
+