add 'encryption uea 1 2' cfg / fix ttcn3 iu tests

Recently, the ability to run UTRAN without encryption was added, but the config
for it was tied to the A5 GERAN encryption configuration. This affected
osmo-msc's default behavior of Iu, breaking osmo-msc ttcn3 Iu tests: the ttcn3
test suite sets A5 to 0 (no encryption) but still expects Iu to enable air
encryption. Fix this "regression".

Add a separate vty config option for UEA encryption, even if it does not
provide full granularity to select individual UEA algorithms yet.

As a result, Iu default behavior remains to enable encryption regardless of the
A5 config. UTRAN encryption can be disabled by the new cfg option
"encryption uea 0" alone.

Even though the new vty command already allows passing various combinations of
the UEA algorithm numbers, only '0' and '1 2' are accepted as valid
combinations, to reflect current osmo-msc capabilities.

Revert most changes to the msc_vlr test suite in commit "do not force
encryption on UTRAN" (I04ecd7a3b1cc603b2e3feb630e8c7c93fc36ccd7): use new
net->iu_encryption instead of net->a5_encryption_mask.

Adjust/add to test_nodes.vty transcript tests.

Related: OS#4144
Change-Id: Ie138f2fcb105533f7bc06a6d2e6deccf6faccc5b

10 files changed, 153 insertions, 62 deletions

diff --git a/doc/manuals/chapters/net.adoc b/doc/manuals/chapters/net.adoc
index 4bf34a33f..6edb9ee3a 100644
--- a/doc/manuals/chapters/net.adoc
+++ b/doc/manuals/chapters/net.adoc
@@ -188,11 +188,22 @@ network
 
 While authentication is always required on 3G, ciphering is optional.
 
-So far OsmoMSC lacks explicit configuration for ciphering on 3G. As an interim
-solution, ciphering is enabled on 3G exactly when ciphering is enabled on 2G,
-i.e. when any cipher other than A5/0 is enabled in the configuration. If only
-A5/0 is configured, ciphering will be disabled on both 2G and 3G. The future
-aim is to add comprehensive configuration for 3G ciphering that is independent
-from the 2G setting.
+So far OsmoMSC allows switching ciphering on 3G either on or off -- the default
+behavior is to enable ciphering. (Individual choice of algorithms may be added
+in the future.)
+
+Disable 3G ciphering:
+
+----
+network
+ encryption uea 0
+----
+
+Enable 3G ciphering (default):
+
+----
+network
+ encryption uea 1 2
+----
 
 OsmoMSC indicates UEA1 and UEA2 as permitted encryption algorithms on 3G.
diff --git a/include/osmocom/msc/gsm_data.h b/include/osmocom/msc/gsm_data.h
index e926b3f87..a90b732af 100644
--- a/include/osmocom/msc/gsm_data.h
+++ b/include/osmocom/msc/gsm_data.h
@@ -149,6 +149,11 @@ struct gsm_network {
 	bool authentication_required;
 	int send_mm_info;
 
+	/* Whether to use encryption on UTRAN.
+	 * TODO: we should offer a choice of UEA1 and/or UEA2, and probably replace this bool with a bit-mask of
+	 * permitted Iu encryption algorithms. See also OS#4143 and the 'encryption uea' vty command. */
+	bool uea_encryption;
+
 	struct rate_ctr_group *msc_ctrs;
 	struct osmo_stat_item_group *statg;
 
diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index cd37cff05..086116fd5 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -375,7 +375,7 @@ static int mm_rx_loc_upd_req(struct msc_a *msc_a, struct msgb *msg)
 				net->vlr, msc_a, vlr_lu_type, tmsi, imsi,
 				&old_lai, &msc_a->via_cell.lai,
 				is_utran || net->authentication_required,
-				net->a5_encryption_mask > 0x01,
+				is_utran ? net->uea_encryption : net->a5_encryption_mask > 0x01,
 				lu->key_seq,
 				osmo_gsm48_classmark1_is_r99(&lu->classmark1),
 				is_utran,
@@ -780,7 +780,7 @@ int gsm48_rx_mm_serv_req(struct msc_a *msc_a, struct msgb *msg)
 			 req->cm_service_type,
 			 mi-1, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 net->a5_encryption_mask > 0x01,
+			 is_utran ? net->uea_encryption : net->a5_encryption_mask > 0x01,
 			 req->cipher_key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, cm2_len),
 			 is_utran);
@@ -1152,7 +1152,7 @@ static int gsm48_rx_rr_pag_resp(struct msc_a *msc_a, struct msgb *msg)
 			 net->vlr, msc_a,
 			 VLR_PR_ARQ_T_PAGING_RESP, 0, mi_lv, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 net->a5_encryption_mask > 0x01,
+			 is_utran ? net->uea_encryption : net->a5_encryption_mask > 0x01,
 			 pr->key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, classmark2_len),
 			 is_utran);
diff --git a/src/libmsc/msc_net_init.c b/src/libmsc/msc_net_init.c
index 11920f377..91b6165bd 100644
--- a/src/libmsc/msc_net_init.c
+++ b/src/libmsc/msc_net_init.c
@@ -49,6 +49,7 @@ struct gsm_network *gsm_network_init(void *ctx, mncc_recv_cb_t mncc_recv)
 
 	/* Permit a compile-time default of A5/3 and A5/1 */
 	net->a5_encryption_mask = (1 << 3) | (1 << 1);
+	net->uea_encryption = true;
 
 	/* Use 30 min periodic update interval as sane default */
 	net->t3212 = 5;
diff --git a/src/libmsc/msc_vty.c b/src/libmsc/msc_vty.c
index 5bf970163..4674e2e68 100644
--- a/src/libmsc/msc_vty.c
+++ b/src/libmsc/msc_vty.c
@@ -144,14 +144,13 @@ DEFUN(cfg_net_name_long,
 	return CMD_SUCCESS;
 }
 
+#define ENCRYPTION_STR "Encryption options\n"
+
 DEFUN(cfg_net_encryption,
       cfg_net_encryption_cmd,
       "encryption a5 <0-3> [<0-3>] [<0-3>] [<0-3>]",
-	"Encryption options\n"
-	"GSM A5 Air Interface Encryption."
-	  " NOTE: as long as OsmoMSC lacks distinct configuration for 3G encryption,"
-	  " 3G encryption is enabled exactly when any 2G encryption is enabled."
-	  " Hence configuring only A5/0 here switches off 3G encryption.\n"
+	ENCRYPTION_STR
+	"GSM A5 Air Interface Encryption.\n"
 	"A5/n Algorithm Number\n"
 	"A5/n Algorithm Number\n"
 	"A5/n Algorithm Number\n"
@@ -166,6 +165,45 @@ DEFUN(cfg_net_encryption,
 	return CMD_SUCCESS;
 }
 
+/* So far just a boolean switch, a future patch might add individual config for UEA1 and UEA2, see OS#4143 */
+DEFUN(cfg_net_encryption_uea,
+      cfg_net_encryption_uea_cmd,
+      "encryption uea <0-2> [<0-2>] [<0-2>]",
+      ENCRYPTION_STR
+      "UTRAN (3G) encryption algorithms to allow: 0 = UEA0 (no encryption), 1 = UEA1, 2 = UEA2."
+        " NOTE: the current implementation does not allow free choice of combining encryption algorithms yet."
+	" The only valid settings are either 'encryption uea 0' or 'encryption uea 1 2'.\n"
+      "UEAn Algorithm Number\n"
+      "UEAn Algorithm Number\n"
+      "UEAn Algorithm Number\n"
+     )
+{
+	unsigned int i;
+	uint8_t mask = 0;
+
+	for (i = 0; i < argc; i++)
+		mask |= (1 << atoi(argv[i]));
+
+	if (mask == (1 << 0)) {
+		/* UEA0. Disable encryption. */
+		gsmnet->uea_encryption = false;
+	} else if (mask == ((1 << 1) | (1 << 2))) {
+		/* UEA1 and UEA2. Enable encryption. */
+		gsmnet->uea_encryption = true;
+	} else {
+		vty_out(vty,
+			"%% Error: the current implementation does not allow free choice of combining%s"
+			"%% encryption algorithms yet. The only valid settings are either%s"
+			"%%   encryption uea 0%s"
+			"%% or%s"
+			"%%   encryption uea 1 2%s",
+			VTY_NEWLINE, VTY_NEWLINE, VTY_NEWLINE, VTY_NEWLINE, VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_net_authentication,
       cfg_net_authentication_cmd,
       "authentication (optional|required)",
@@ -308,6 +346,11 @@ static int config_write_net(struct vty *vty)
 			vty_out(vty, " %u", i);
 	}
 	vty_out(vty, "%s", VTY_NEWLINE);
+
+	if (!gsmnet->uea_encryption)
+		vty_out(vty, " encryption uea 0%s", VTY_NEWLINE);
+	else
+		vty_out(vty, " encryption uea 1 2%s", VTY_NEWLINE);
 	vty_out(vty, " authentication %s%s",
 		gsmnet->authentication_required ? "required" : "optional", VTY_NEWLINE);
 	vty_out(vty, " rrlp mode %s%s", msc_rrlp_mode_name(gsmnet->rrlp.mode),
@@ -1894,6 +1937,7 @@ void msc_vty_init(struct gsm_network *msc_network)
 	install_element(GSMNET_NODE, &cfg_net_name_short_cmd);
 	install_element(GSMNET_NODE, &cfg_net_name_long_cmd);
 	install_element(GSMNET_NODE, &cfg_net_encryption_cmd);
+	install_element(GSMNET_NODE, &cfg_net_encryption_uea_cmd);
 	install_element(GSMNET_NODE, &cfg_net_authentication_cmd);
 	install_element(GSMNET_NODE, &cfg_net_rrlp_mode_cmd);
 	install_element(GSMNET_NODE, &cfg_net_mm_info_cmd);
diff --git a/tests/msc_vlr/msc_vlr_test_authen_reuse.c b/tests/msc_vlr/msc_vlr_test_authen_reuse.c
index 62ea6c7b5..d73a5f8c5 100644
--- a/tests/msc_vlr/msc_vlr_test_authen_reuse.c
+++ b/tests/msc_vlr/msc_vlr_test_authen_reuse.c
@@ -266,8 +266,6 @@ static void _test_auth_reuse(enum osmo_rat_type via_ran,
 static void test_auth_use_twice_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_auth_reuse(OSMO_RAT_GERAN_A, 1, 1, true);
 	comment_end();
 }
@@ -275,8 +273,6 @@ static void test_auth_use_twice_geran()
 static void test_auth_use_twice_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
 	_test_auth_reuse(OSMO_RAT_UTRAN_IU, 1, 1, true);
 	comment_end();
 }
@@ -284,8 +280,6 @@ static void test_auth_use_twice_utran()
 static void test_auth_use_infinitely_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_auth_reuse(OSMO_RAT_GERAN_A, -1, 3, false);
 	comment_end();
 }
@@ -293,8 +287,6 @@ static void test_auth_use_infinitely_geran()
 static void test_auth_use_infinitely_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
 	_test_auth_reuse(OSMO_RAT_UTRAN_IU, -1, 3, false);
 	comment_end();
 }
@@ -302,8 +294,6 @@ static void test_auth_use_infinitely_utran()
 static void test_no_auth_reuse_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_auth_reuse(OSMO_RAT_GERAN_A, 0, 0, true);
 	comment_end();
 }
@@ -311,8 +301,6 @@ static void test_no_auth_reuse_geran()
 static void test_no_auth_reuse_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
 	_test_auth_reuse(OSMO_RAT_UTRAN_IU, 0, 0, true);
 	comment_end();
 }
diff --git a/tests/msc_vlr/msc_vlr_test_call.c b/tests/msc_vlr/msc_vlr_test_call.c
index cec2f8da0..065af2555 100644
--- a/tests/msc_vlr/msc_vlr_test_call.c
+++ b/tests/msc_vlr/msc_vlr_test_call.c
@@ -46,7 +46,6 @@ static void standard_lu()
 	struct vlr_subscr *vsub;
 
 	net->authentication_required = true;
-	net->a5_encryption_mask = A5_0_3;
 	net->vlr->cfg.assign_tmsi = true;
 	rx_from_ran = OSMO_RAT_UTRAN_IU;
 
diff --git a/tests/msc_vlr/msc_vlr_test_umts_authen.c b/tests/msc_vlr/msc_vlr_test_umts_authen.c
index 1bf6cd217..761db55e2 100644
--- a/tests/msc_vlr/msc_vlr_test_umts_authen.c
+++ b/tests/msc_vlr/msc_vlr_test_umts_authen.c
@@ -49,6 +49,8 @@ static void _test_umts_authen(enum osmo_rat_type via_ran)
 		"5079da1e1ee7416937485e9ea7c965373d1d6683c270383b3d0e"
 		"d3d36ff71c949e83c22072799e9687c5ec32a81d96afcbf4b4fb"
 		"0c7ac3e9e9b7db05";
+	bool encryption = (via_ran == OSMO_RAT_GERAN_A && net->a5_encryption_mask > 0x1)
+		|| (via_ran == OSMO_RAT_UTRAN_IU && net->uea_encryption);
 
 	net->authentication_required = true;
 	net->vlr->cfg.assign_tmsi = true;
@@ -122,8 +124,7 @@ static void _test_umts_authen(enum osmo_rat_type via_ran)
 	VERBOSE_ASSERT(auth_request_sent, == true, "%d");
 	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
 
-	if (net->a5_encryption_mask > 0x1) {
-		/* Encryption enabled */
+	if (encryption) {
 		if (via_ran == OSMO_RAT_GERAN_A) {
 			btw("Test code not implemented");
 			OSMO_ASSERT(false);
@@ -197,8 +198,7 @@ static void _test_umts_authen(enum osmo_rat_type via_ran)
 	EXPECT_ACCEPTED(false);
 	thwart_rx_non_initial_requests();
 
-	if (net->a5_encryption_mask > 0x1) {
-		/* Encryption enabled */
+	if (encryption) {
 		if (via_ran == OSMO_RAT_GERAN_A) {
 			btw("Test code not implemented");
 			OSMO_ASSERT(false);
@@ -265,8 +265,7 @@ static void _test_umts_authen(enum osmo_rat_type via_ran)
 	EXPECT_ACCEPTED(false);
 	thwart_rx_non_initial_requests();
 
-	if (net->a5_encryption_mask > 0x1) {
-		/* Encryption enabled */
+	if (encryption) {
 		if (via_ran == OSMO_RAT_GERAN_A) {
 			btw("Test code not implemented");
 			OSMO_ASSERT(false);
@@ -327,8 +326,6 @@ static void _test_umts_authen(enum osmo_rat_type via_ran)
 static void test_umts_authen_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_umts_authen(OSMO_RAT_GERAN_A);
 	comment_end();
 }
@@ -336,8 +333,7 @@ static void test_umts_authen_geran()
 static void test_umts_authen_utran()
 {
 	comment_start();
-	/* A5/0 = no encryption; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0;
+	net->uea_encryption = false;
 	_test_umts_authen(OSMO_RAT_UTRAN_IU);
 	comment_end();
 }
@@ -345,8 +341,7 @@ static void test_umts_authen_utran()
 static void test_umts_auth_ciph_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
+	net->uea_encryption = true;
 	_test_umts_authen(OSMO_RAT_UTRAN_IU);
 	comment_end();
 }
@@ -365,6 +360,8 @@ static void _test_umts_authen_resync(enum osmo_rat_type via_ran)
 {
 	struct vlr_subscr *vsub;
 	const char *imsi = "901700000010650";
+	bool encryption = (via_ran == OSMO_RAT_GERAN_A && net->a5_encryption_mask > 0x1)
+		|| (via_ran == OSMO_RAT_UTRAN_IU && net->uea_encryption);
 
 	net->authentication_required = true;
 	net->vlr->cfg.assign_tmsi = true;
@@ -519,8 +516,7 @@ static void _test_umts_authen_resync(enum osmo_rat_type via_ran)
 	VERBOSE_ASSERT(auth_request_sent, == true, "%d");
 	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
 
-	if (net->a5_encryption_mask > 0x1) {
-		/* Encryption enabled */
+	if (encryption) {
 		if (via_ran == OSMO_RAT_GERAN_A) {
 			btw("Test code not implemented");
 			OSMO_ASSERT(false);
@@ -585,8 +581,6 @@ static void _test_umts_authen_resync(enum osmo_rat_type via_ran)
 static void test_umts_authen_resync_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_umts_authen_resync(OSMO_RAT_GERAN_A);
 	comment_end();
 }
@@ -594,8 +588,7 @@ static void test_umts_authen_resync_geran()
 static void test_umts_authen_resync_utran()
 {
 	comment_start();
-	/* A5/0 = no encryption; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0;
+	net->uea_encryption = false;
 	_test_umts_authen_resync(OSMO_RAT_UTRAN_IU);
 	comment_end();
 }
@@ -603,8 +596,7 @@ static void test_umts_authen_resync_utran()
 static void test_umts_auth_ciph_resync_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
+	net->uea_encryption = true;
 	_test_umts_authen_resync(OSMO_RAT_UTRAN_IU);
 	comment_end();
 }
@@ -698,8 +690,6 @@ static void _test_umts_authen_too_short_res(enum osmo_rat_type via_ran)
 static void test_umts_authen_too_short_res_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_umts_authen_too_short_res(OSMO_RAT_GERAN_A);
 	comment_end();
 }
@@ -707,8 +697,6 @@ static void test_umts_authen_too_short_res_geran()
 static void test_umts_authen_too_short_res_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
 	_test_umts_authen_too_short_res(OSMO_RAT_UTRAN_IU);
 	comment_end();
 }
@@ -802,8 +790,6 @@ static void _test_umts_authen_too_long_res(enum osmo_rat_type via_ran)
 static void test_umts_authen_too_long_res_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_umts_authen_too_long_res(OSMO_RAT_GERAN_A);
 	comment_end();
 }
@@ -811,8 +797,6 @@ static void test_umts_authen_too_long_res_geran()
 static void test_umts_authen_too_long_res_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
 	_test_umts_authen_too_long_res(OSMO_RAT_UTRAN_IU);
 	comment_end();
 }
@@ -911,8 +895,6 @@ static void _test_umts_authen_only_sres(enum osmo_rat_type via_ran)
 static void test_umts_authen_only_sres_geran()
 {
 	comment_start();
-	/* A5/0 = no encryption */
-	net->a5_encryption_mask = A5_0;
 	_test_umts_authen_only_sres(OSMO_RAT_GERAN_A);
 	comment_end();
 }
@@ -920,8 +902,6 @@ static void test_umts_authen_only_sres_geran()
 static void test_umts_authen_only_sres_utran()
 {
 	comment_start();
-	/* A5/0 + A5/3 = encryption enabled; so far the A5 setting also triggers UTRAN encryption */
-	net->a5_encryption_mask = A5_0_3;
 	_test_umts_authen_only_sres(OSMO_RAT_UTRAN_IU);
 	comment_end();
 }
diff --git a/tests/msc_vlr/msc_vlr_tests.h b/tests/msc_vlr/msc_vlr_tests.h
index 4330ea869..9df9cf049 100644
--- a/tests/msc_vlr/msc_vlr_tests.h
+++ b/tests/msc_vlr/msc_vlr_tests.h
@@ -32,9 +32,6 @@
 #include <osmocom/msc/msc_a.h>
 #include <osmocom/msc/mncc.h>
 
-#define A5_0 (1 << 0)
-#define A5_0_3 ((1 << 0) | (1 << 3))
-
 extern bool _log_lines;
 #define _log(fmt, args...) do { \
 		if (_log_lines) \
diff --git a/tests/test_nodes.vty b/tests/test_nodes.vty
index fb7b1c529..0ad390fc5 100644
--- a/tests/test_nodes.vty
+++ b/tests/test_nodes.vty
@@ -17,6 +17,7 @@ OsmoMSC(config-net)# list
   short name NAME
   long name NAME
   encryption a5 <0-3> [<0-3>] [<0-3>] [<0-3>]
+  encryption uea <0-2> [<0-2>] [<0-2>]
   authentication (optional|required)
   rrlp mode (none|ms-based|ms-preferred|ass-preferred)
   mm info (0|1)
@@ -26,6 +27,21 @@ OsmoMSC(config-net)# list
   periodic location update <6-1530>
   no periodic location update
 
+OsmoMSC(config-net)# encryption?
+  encryption  Encryption options
+OsmoMSC(config-net)# encryption ?
+  a5   GSM A5 Air Interface Encryption.
+  uea  UTRAN (3G) encryption algorithms to allow: 0 = UEA0 (no encryption), 1 = UEA1, 2 = UEA2. NOTE: the current implementation does not allow free choice of combining encryption algorithms yet. The only valid settings are either 'encryption uea 0' or 'encryption uea 1 2'.
+
+OsmoMSC(config-net)# encryption uea ?
+  <0-2>  UEAn Algorithm Number
+OsmoMSC(config-net)# encryption uea 0 ?
+  [<0-2>]  UEAn Algorithm Number
+OsmoMSC(config-net)# encryption uea 0 1 ?
+  [<0-2>]  UEAn Algorithm Number
+OsmoMSC(config-net)# encryption uea 0 1 2 ?
+  <cr>  
+
 OsmoMSC(config-net)# exit
 OsmoMSC(config)# msc
 OsmoMSC(config-msc)# list
@@ -130,6 +146,7 @@ network
  short name OsmoMSC
  long name OsmoMSC
  encryption a5 0
+ encryption uea 1 2
  authentication optional
  rrlp mode none
  mm info 1
@@ -157,3 +174,52 @@ sgs
  local-ip 0.0.0.0
  vlr-name vlr.example.net
 end
+
+OsmoMSC# configure terminal
+OsmoMSC(config)# network
+OsmoMSC(config-net)# encryption uea 0
+OsmoMSC(config-net)# show running-config
+...
+ encryption uea 0
+...
+
+OsmoMSC(config-net)# encryption uea 1
+% Error: the current implementation does not allow free choice of combining
+% encryption algorithms yet. The only valid settings are either
+%   encryption uea 0
+% or
+%   encryption uea 1 2
+OsmoMSC(config-net)# show running-config
+...
+ encryption uea 0
+...
+
+OsmoMSC(config-net)# encryption uea 2
+% Error: the current implementation does not allow free choice of combining
+...
+OsmoMSC(config-net)# show running-config
+...
+ encryption uea 0
+...
+
+OsmoMSC(config-net)# encryption uea 0 1
+% Error: the current implementation does not allow free choice of combining
+...
+OsmoMSC(config-net)# show running-config
+...
+ encryption uea 0
+...
+
+OsmoMSC(config-net)# encryption uea 0 2
+% Error: the current implementation does not allow free choice of combining
+...
+OsmoMSC(config-net)# show running-config
+...
+ encryption uea 0
+...
+
+OsmoMSC(config-net)# encryption uea 1 2
+OsmoMSC(config-net)# show running-config
+...
+ encryption uea 1 2
+...