CoAP with DTLS 1.2 on nRF9160

RE: CoAP with DTLS 1.2 on nRF9160

Øyvind — Tue, 02 Nov 2021 08:52:05 GMT

Could you please elaborate more on what you are trying to achieve? From our modem FW release notes it states:

*** Limitations
***************
- TLS/DTLS
    - Up to three simultaneous TLS/DTLS connections are possible.
    - Maximum server certificate chain size has a limit of 4kB.
    - Server certificate expiry time is not verified.
    - pkcs#8 is not supported.
    - Absolute maximum number of supported credentials is 32. The actual amount depends on size of
      credentials as memory area reserved for credentials may be a limiting factor as well.
    - DTLS supports PSK authentication only.
    - 2kB secure socket buffer size.

So PSK based DTLS is supported.

[quote user="Andre23t"]What approach would you recommend to find some examples for using CoAP with PSK-based DTLS authentication?[/quote]

We have several samples in which TLS/DTLS is used, I recommend looking through our official nRF9160 samples, and the modem library documentation on TLS/DTLS configuration

RE: CoAP with DTLS 1.2 on nRF9160

Andre23t — Mon, 01 Nov 2021 19:12:01 GMT

Thanks for your answer Øyvind! I am using NCS 1.7.1 and will examine the download client sample , thanks for that. Having a first look to the source code of nordic_nrf_9160/sdk-nrf/samples/nrf9160/download/src/main.c it seems like the sample is using certificate for authentication both for HTTP and CoAP. What approach would you recommend to find some examples for using CoAP with PSK-based DTLS authentication? Thanks for any hint

RE: CoAP with DTLS 1.2 on nRF9160

Øyvind — Mon, 01 Nov 2021 12:49:18 GMT

Hi Andre,

What version of NCS are you working on? The Download client library can use CoAPS (DTLS 1.2). Have a look at the nRF9160: Download client sample.

Kind regards,
Øyvind