how to transmitt encryption data with nRF51 SDK9 hrm example?

RE: how to transmitt encryption data with nRF51 SDK9 hrm example?

Hung Bui — Wed, 05 Apr 2017 15:29:25 GMT

If you see the phone is bonded to your device, then the link is encrypted. Check the bonding list in Bluetooth setting in the phone.

RE: how to transmitt encryption data with nRF51 SDK9 hrm example?

Mikhail — Wed, 05 Apr 2017 14:06:14 GMT

Thanks. therefore, for crypted characteristics, my code like above is enought and correct? Or does it have another method for crypted data?

RE: how to transmitt encryption data with nRF51 SDK9 hrm example?

Hung Bui — Wed, 05 Apr 2017 14:00:50 GMT

If you set BLE_GAP_CONN_SEC_MODE_SET_ENC_WITH_MITM() to the characteristic, encryption will be required when the central want to read your data. And then you will get a popup on the phone to ask for pairing.

After you pair, the link will be encrypted. But note that, the application will still show the normal data value when you read the characteristic, just because the encryption happens on lower layer and it's transparent to the application.

RE: how to transmitt encryption data with nRF51 SDK9 hrm example?

Mikhail — Wed, 05 Apr 2017 09:16:10 GMT

Thanks for answer. I use HRS example on nRF51 and I want to understand about encryption. How to do it. So, on nRF51 I run HRS example in advertise mode. On central (smartfone application nRF connect) I can see data. Battery level for example. When on HRS project I add into

static void gap_params_init(void) ()

code like on 1st post, on the smartfone I can see all my data without any encryption. For ex, I can see battery level. What I should do for crypted this data? For crypted battery level for ex? I suppose, I need add in

static void services_init(void)
    BLE_GAP_CONN_SEC_MODE_SET_ENC_WITH_MITM(&bas_init.battery_level_char_attr_md.cccd_write_perm); 
BLE_GAP_CONN_SEC_MODE_SET_ENC_WITH_MITM(&bas_init.battery_level_char_attr_md.read_perm); 
BLE_GAP_CONN_SEC_MODE_SET_ENC_WITH_MITM(&bas_init.battery_level_char_attr_md.write_perm);

BLE_GAP_CONN_SEC_MODE_SET_ENC_WITH_MITM(&bas_init.battery_level_report_read_perm);

instead of

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&bas_init.battery_level_char_attr_md.cccd_write_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&bas_init.battery_level_char_attr_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&bas_init.battery_level_char_attr_md.write_perm);

BLE_GAP_CONN_SEC_MODE_SET_OPEN(&bas_init.battery_level_report_read_perm);

Is it correct? If I want to crypted one of charecteristic? Or is there method to cripted all data?

RE: how to transmitt encryption data with nRF51 SDK9 hrm example?

Hung Bui — Wed, 05 Apr 2017 07:47:06 GMT

@Mikhail: please give more information on how you test it. What you meant by "see" and "can't see" ? which tool did you use ? Which central device?

RE: how to transmitt encryption data with nRF51 SDK9 hrm example?

Mikhail — Tue, 04 Apr 2017 10:56:41 GMT

Thanks for answer. With only code like in 1-st post

static void gap_params_init(void) ()

I don't have encrypted dsta. Any data of charactericstic I can see without encryption. But if I add in characteristic property encription, I can't see data in that characteristic.

RE: how to transmitt encryption data with nRF51 SDK9 hrm example?

Hung Bui — Tue, 04 Apr 2017 10:22:18 GMT

Hi Mikhail,

Do did you check if the data was encrypted or not ?

The easiest way is to encrypt data is to pair/bond your phone with the device. After pairing/bonding, the communication between the phone and the device is encrypted with AES128.

The passkey configuration is part of the pairing process when you want to have MITM protection.

But you need to start pairing first. Please try to test with our proximity example where bonding is required to read a characteristic.

I would suggest you to have a look at a BLE book to have a rough overview of how BLE security works for example "Bluetooth Low Energy: The Developer's Handbook" , "Getting Started with Bluetooth Low Energy: Tools and Techniques for Low-Power Networking" or have a look here.