Re: [lwip-users] MQTT using lwip/pppos secure communication

[Giuseppe Modugno]

Hello Thomas,

I actually involved in a project similar to yours: NXP MCU (LPC1768) 
that connects to AWS IoT Core through MQTT over TLS.

It is complex, in my case because of limited RAM (only internal 
32k+32kB). I hope you have more space.

Anyway I was able to connect to AWS including lwip and mbedTLS and fine 
tuning some configuration parameters, mainly the dimensions of buffers.

You have to create a device in AWS and create certificates that you must 
include in your project. The problem here is the cryptography. Read 
here[1] how to create and use EC-based certificates that use much less 
RAM space.

Other improvementes in RAM usage can be obtained with some mbedTLS 
configurations. An hint: grab mbedTLS directly from git.

Does your application make a connection with AWS only?

[1] 
https://aws.amazon.com/it/blogs/iot/elliptic-curve-cryptography-and-forward-secrecy-support-in-aws-iot-3/

Il 08/06/2019 11:21, john vargh ha scritto:
> Hello,
>
> I am using NXP micro, with LWIP version 2.1.2
> I have successfully established the MQTT communication with Mosquitto 
> server.
>
> Now, I want to communicate with Amazon server, using secure MQTT.
> I want to know the basic steps OR which calls to use to INIT the process.
> [ client & server handshake with certs.]
>
> Any one as tried, just need to know the which calls to be used to get 
> started.
>
> MQTT_DO_CONNECT...
>
> Thomas
>
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