diff --git a/src/tests/hnb-test-layers.h b/src/tests/hnb-test-layers.h
index 4b17461..7ab273a 100644
--- a/src/tests/hnb-test-layers.h
+++ b/src/tests/hnb-test-layers.h
@@ -13,3 +13,4 @@
 
 /* RANAP calls main with actual payload*/
 void hnb_test_nas_rx_dtap(struct hnb_test *hnb, void *data, int len);
+void hnb_test_rx_secmode_cmd(struct hnb_test *hnb, long ip_alg);
diff --git a/src/tests/hnb-test-ranap.c b/src/tests/hnb-test-ranap.c
index 63e3d92..4986e98 100644
--- a/src/tests/hnb-test-ranap.c
+++ b/src/tests/hnb-test-ranap.c
@@ -17,6 +17,8 @@
 {
 	int len;
 	char *data;
+	RANAP_PermittedIntegrityProtectionAlgorithms_t *algs;
+	RANAP_IntegrityProtectionAlgorithm_t *first_alg;
 
 	printf("rx ranap_msg->procedureCode %d\n",
 	       ranap_msg->procedureCode);
@@ -32,5 +34,21 @@
 
 		hnb_test_nas_rx_dtap(hnb, data, len);
 		return;
+
+	case RANAP_ProcedureCode_id_SecurityModeControl:
+		printf("rx SecurityModeControl: presence = %hx\n",
+		       ranap_msg->msg.securityModeCommandIEs.presenceMask);
+
+		/* Just pick the first available IP alg, don't care about
+		 * encryption (yet?) */
+		algs = &ranap_msg->msg.securityModeCommandIEs.integrityProtectionInformation.permittedAlgorithms;
+		if (algs->list.count < 1) {
+			printf("Security Mode Command: No permitted algorithms.\n");
+			return;
+		}
+		first_alg = *algs->list.array;
+
+		hnb_test_rx_secmode_cmd(hnb, *first_alg);
+		return;
 	}
 }
diff --git a/src/tests/hnb-test.c b/src/tests/hnb-test.c
index 9af5085..603f63b 100644
--- a/src/tests/hnb-test.c
+++ b/src/tests/hnb-test.c
@@ -432,6 +432,13 @@
 	}
 }
 
+void hnb_test_rx_secmode_cmd(struct hnb_test *hnb, long ip_alg)
+{
+	printf(" :) Security Mode Command :)\n");
+	/* not caring about encryption yet, just pass 0 for No Encryption. */
+	hnb_test_tx_dt(hnb, ranap_new_msg_sec_mod_compl(ip_alg, 0));
+}
+
 int hnb_test_hnbap_rx(struct hnb_test *hnb, struct msgb *msg)
 {
 	HNBAP_PDU_t _pdu, *pdu = &_pdu;