Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Fri, 12 Apr 2019 13:41:02 GMT

Hi! Thanks.

I'll write you later, after Easter. Before it, I try to accumulate more information.

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Fri, 12 Apr 2019 13:36:44 GMT

Hi Mikhail

It didn't use directed advertising, no. Based on the log it is normal, un-directed advertising.

It might have used whitelist, but whitelisting doesn't make the advertise packet invisible to other scanners. It only means that other scanners will not get a response if they try to send a scan or connection request to the advertiser.

When you say other platforms, did you also test in nRF Connect for Desktop?

Unfortunately I won't be able to follow this up until after Easter, as I am leaving for vacation (I'm back in office on the 23rd of April).

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Fri, 12 Apr 2019 08:12:10 GMT

Hi!

I run nRF Connect on a android platform.

I tested this sniffed adv device on another platforms- same behavior- can't see in the nrf connect.

But in the another mode of this device I can see it in the nrf connect. But I can't see it only in this mode. See only in ble sniffer.

My be it used direct advertise mode ? Or it used whitelist for advertise?

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Thu, 11 Apr 2019 12:30:05 GMT

Hi Mikhail

Thanks for the sniffer log.

Based on this I can't see why the packet shouldn't show up in nRF Connect. It looks like normal advertising to me.

What platform/phone are you running nRF Connect on?

Do you have some other platform available that you can test on, to see if it doesn't show up there either?

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Tue, 09 Apr 2019 08:10:48 GMT

https://drive.google.com/file/d/16DzY4MQ0KPc5IPIK1UFsdZsiD96hLjRP/view?usp=sharing

This is link to same device wich advertise and I can't see it in the nrf Connect.

Also I don't want to use bypass SD. I want to use SD and want to make invisible only in the nrf Connect via standart functions.

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Tue, 09 Apr 2019 06:22:20 GMT

You might have to bypass the SoftDevice to do this. If you access the radio directly you get full control of the data payload, and you can send any type of packet that you like.

Are you able to send me the information from the sniffer showing the data content of this packet?

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Fri, 05 Apr 2019 14:20:16 GMT

Hi! Sorrry for delay with answer.

No! I need make my device like sniffed device. I mean- this sniffed device doesn't see in nRF connect. I see this device only in the wire shark sniffer. How to make my device with same behavoir? I mean- unvisible in the nRF connect?

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Mon, 04 Mar 2019 12:57:17 GMT

Hi Mikhail

I am a bit unsure what you are asking for.

Are you looking for the code needed to make the nRF52 device duplicate the packet from the device you are sniffing?

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Mon, 18 Feb 2019 08:53:31 GMT

Hi!

I have sniff same device which is not visible in the nRF connect and visible in the sniffer.

I need make same. How it made in this sniffed device?

download from link (wireshark):

drive.google.com/.../view

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Wed, 30 Jan 2019 08:41:39 GMT

You can't really hide the advertise packet from nRF Connect if you want to advertise to many devices, but you can change the payload if you like. For instance you can remove the advertising name, and only advertise the advertising flags and your BLE address.

You can also make the address of your advertiser private resolvable, which means the address will change periodically so that nRF Connect can not track your advertiser over time. Devices that are bonded to you can still recognize the advertiser, because they can resolve a static address from the private resolvable one.

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Tue, 29 Jan 2019 08:02:57 GMT

Hi!

Thanks. It is clear. But I interesting- just hide my advertise device from nRF connect util. As I understand, if I need advertise for many devices- one way it hide name. Or I miss one more opportunity?

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Mon, 21 Jan 2019 15:32:09 GMT

There are two methods to limit the number of devices that can send connection or scan requests:

1) Directed advertising, as described below. This only allows you to connect to a single device, and you will skip all the normal fields in the advertising payload.

2) Advertising with white list: In this mode you don't change the content of the advertising payload, and everyone can read the advertising packet, but you will only accept connection requests or scan requests from devices that are stored in your white list.

The advantage of this method is that you can have more than one device in the white list, but the drawback is that other devices can still read your advertising payload (if you want you could always remove the data fields from the adv packet if the devices in your white list don't need this data).

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Mon, 21 Jan 2019 11:51:32 GMT

Thanks. So, if I want just advertise for a few devices, is there only one method- no name? Isn't it?

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Mon, 21 Jan 2019 08:12:23 GMT

You have to set the address of the device you want to connect to in the p_peer_addr field of the ble_gap_adv_params_t struct when you configure advertising.

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Fri, 18 Jan 2019 13:24:25 GMT

Thanks,

after device has bonded, which settings in the nRF52 should change to direct advertise?

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

ovrebekk — Thu, 17 Jan 2019 14:18:41 GMT

After you have bonded to a device you can switch to directed advertising, which means you are advertising just to reconnect to that particular device.

In directed advertising mode you don't include any of the normal data fields (name, UUID and so forth), just the BLE address of the device you want to connect to, and nRF Connect should not show anything.

For more information about the different advertising types please have a look at the following article:
https://blog.bluetooth.com/advertising-works-part-1

Best regards
Torbjørn

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Stefan Wyss — Thu, 17 Jan 2019 09:14:08 GMT

Yes, there is an answer: It is not possible to hide advertizing packets, because all advertizements are visible to scanners.

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Mikhail — Wed, 16 Jan 2019 15:14:40 GMT

Thanks, but I seen this. And there is no answer to my question.

RE: Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

Stefan Wyss — Tue, 15 Jan 2019 15:51:22 GMT

I'm a absolute beginner, but maybe I can still give you some advice based on what I found on this forum:

Basically all advertisements are visible to all scanners. But the scanners can assume that:

if the Limited discoverable mode is used the device will only advertise for a limited amount of time. e.g. the user has put the device in bondable mode or some other time limited mode.
If a scanner sees a "non discoverable" advertisement it can assume this device uses a whitelist or for some other reason is not connectable. So it can save power by not trying to connect.
But I'm afraid the behavior will depend on the implementation, as it's up to the developer to use these flags correctly. Unless you are implementing a sig define profile with given requirements for flags.