RE: nRF9160: Offloaded TLS vs. Mbed TLS

Stefan Schmidt — Mon, 10 Jun 2024 11:43:25 GMT

The major drawback of the offloaded TLS is the limitation of the secure buffers (2 kB)

RE: nRF9160: Offloaded TLS vs. Mbed TLS

Kazi Afroza Sultana — Wed, 13 Dec 2023 16:07:44 GMT

Hello,

In terms of ''modem's offloaded TLS capabilities vs. Mbed TLS'', there are differences between them. But it depends on the modem version.

I do not know about power consumption. It probably depends on how the ''native'' TLS is configured. The modem has some HW acceleration. So, there should not have too many differences. Power consumption is dominated by radio also.

On the application core, we have the cryptocell, but it might also configure the libraries to use SW implementations, and in that case, we would expect the performance to be worse on the application side. In terms of performance, you could argue that there is no performance cost when using offloaded TLS, as then the heavy computation happens on the modem side, and the application core is free to do other things.

Regarding memory footprint, when using offloaded TLS, the cost is on the modem side, where you do not get any benefit from not using it, while on the application side, you will lose a lot of flash and RAM that the application could have used otherwise.

From a security point of view, we recommend using offloaded TLS, as then the keys won't be accessible by the application at all.

So in general, we recommend offloaded TLS in all cases, unless the TLS stack in the modem is missing some features that they absolutely need. I.e. the only benefit of "native" TLS is the extra configurability.

RE: nRF9160: Offloaded TLS vs. Mbed TLS

Kazi Afroza Sultana — Wed, 13 Dec 2023 12:46:49 GMT

Hello,

I have been looking at your case. I will get back to you soon.

Thanks.

Kazi