How to set up nrf52833 Security 2 Level 2?

[Mikey]

Hi,

I looked at some of the questions on the forum and they didn't give me good advice. Currently all I can do is nrf52832 Security 1 Level 4 and nrf52833 Security 1 Level 3. But according to my bluetooth protocol requirement is Security 2 Level 2 of nrf52833. But I have any good suggestions for finding a proper way to implement it? I use SDK17.1, softdevice s140 7.3.0.

Thank you,

wfagly.

[Simonr]

Hi

Security mode 2 (or more specifically data signing) is not supported in any of the SoftDevices in the nRF5 SDK. From what I have heard, data signing is in general not very widely used as most phones on the market doesn't support this feature either.

The alternative will be to use the nRF Connect SDK where data signing is supported and should work. The GAP security features in Zephyr are described here, and data signing here in the Zephyr project.

Best regards,

Simon

[Mikey]

Hi,

That is to say, if I want to use these digital signature functions, I have to change another SDK and change another zephyr os to support these functions.

[Simonr]

That is correct. And as Emil suggests, security mode 1 is generally a better security implementation all around. 

[Mikey]

Should I choose level3 or level4 in security mode 1?

[Emil Lenngren]

The difference between level 3 and 4 is the use of "LE Secure Connections". If you already know that both devices (central and peripheral) support LESC, then do require the use of LESC during pairing, since the legacy methods are all considered unsecure. If you only intend to communicate with Android, iOS and other "big" operating systems, there is no need to support the legacy methods since these systems have support for LESC since a long time ago.