Allow LESC "Just Works" Pairing/Bonding with NRF Connect SDK (Zephyr) after pressing Button

[nexus]

Hi

Is there an example for BLE "Just Works" using the NRF Connect SDK for the peripheral device?

I am using a peripheral device without display and would like to allow pairing / bonding for a short period of time after pressing a button.

Having registered callbacks using bt_conn_auth_cb and setting .passkey_display = NULL and .passkey_confirm = NULL does result in being able to pair and bond, yet I would like to only allow bonding in case a button has been pressed before.

Registering pairing_confirm and calling bt_conn_auth_cancel (in case pairing is not allowd) has not yielded the desired outcome so far and I am wondering if this is at all possible (the above pattern used to work with the nRF5 SDK).

Any advise would be appreciated!

Best
Manuel

[jpf]

Hello,

Have you found any solution to this? I am trying to achieve something similar by using pairing_confirm callback and the bt_conn_auth_pairing_confirm function to wait for an input before confirming pairing.

My setup is very similar. Based on the peripheral_uart sample I set bt_conn_auth_cb .passkey_display = NULL and .passkey_confirm = NULL, but keep .pairing_confirm active.

Whatever I do this results in a timeout during pairing/bonding, even though bt_conn_auth_pairing_confirm is called either inside .pairing_confirm or asynchronously when a button is pressed.

Best

Jonas

[Simon]

Hello Jonas,

I'll take a look at this.

Best regards,

Simon

[jpf]

Hi Simon,

Thank you for your time. I found a solution for this. Here is my diff compared to the peripheral_uart sample:

diff --git a/applications/peripheral_uart/prj.conf b/applications/peripheral_uart/prj.conf
index e5262de..881a897 100644
--- a/applications/peripheral_uart/prj.conf
+++ b/applications/peripheral_uart/prj.conf
@@ -22,7 +22,7 @@ CONFIG_BT_PERIPHERAL=y
 CONFIG_BT_DEVICE_NAME="Nordic_UART_Service"
 CONFIG_BT_DEVICE_APPEARANCE=833
 CONFIG_BT_MAX_CONN=1
-CONFIG_BT_MAX_PAIRED=1
+CONFIG_BT_MAX_PAIRED=2
 
 # Enable the NUS service
 CONFIG_BT_NUS=y
@@ -45,6 +45,6 @@ CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
 CONFIG_LOG=y
 CONFIG_USE_SEGGER_RTT=y
 CONFIG_LOG_BACKEND_RTT=y
-CONFIG_LOG_BACKEND_UART=n
+CONFIG_LOG_BACKEND_UART=y
 
 CONFIG_ASSERT=y
diff --git a/applications/peripheral_uart/src/main.c b/applications/peripheral_uart/src/main.c
index ee72be1..529b3a9 100644
--- a/applications/peripheral_uart/src/main.c
+++ b/applications/peripheral_uart/src/main.c
@@ -421,9 +421,9 @@ static void pairing_confirm(struct bt_conn *conn)
 
 	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
-	bt_conn_auth_pairing_confirm(conn);
+	auth_conn = bt_conn_ref(conn);
 
-	LOG_INF("Pairing confirmed: %s", log_strdup(addr));
+	LOG_INF("Please confirm pairing: %s", log_strdup(addr));
 }
 
 
@@ -450,8 +450,8 @@ static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
 
 
 static struct bt_conn_auth_cb conn_auth_callbacks = {
-	.passkey_display = auth_passkey_display,
-	.passkey_confirm = auth_passkey_confirm,
+	.passkey_display = NULL,
+	.passkey_confirm = NULL,
 	.cancel = auth_cancel,
 	.pairing_confirm = pairing_confirm,
 	.pairing_complete = pairing_complete,
@@ -525,11 +525,11 @@ void error(void)
 static void num_comp_reply(bool accept)
 {
 	if (accept) {
-		bt_conn_auth_passkey_confirm(auth_conn);
-		LOG_INF("Numeric Match, conn %p", (void *)auth_conn);
+		int ret = bt_conn_auth_pairing_confirm(auth_conn);
+		LOG_INF("Pairing confirmed");
 	} else {
 		bt_conn_auth_cancel(auth_conn);
-		LOG_INF("Numeric Reject, conn %p", (void *)auth_conn);
+		LOG_INF("Pairing rejected");
 	}
 
 	bt_conn_unref(auth_conn);

[Simon]

There you go, thanks for sharing the solution!