I've seen the post in the blog using the SSL client for secure MQTT, isn't possible to place in the i2c bus the ATECC608B crypto accelerator for ease the work, and save some flash (for certificate storage)?

Enrico Michieletti
Enrico Michieletti
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Asked on 4/16/21, 8:10 PM

Hi, i'm not familiar with that IC, but i am using the MQTT over SSL in a sketch with a dozen libraries and 4000+ lines of code, and it only fills 48% of the 256KB available so i'm not sure you will run out of flash easily. In my understanding, you only need to store 1 self-signed certificate to avoid expiring CA certificates. Furthermore, your IDC expansion port will be occupied by an Ethernet or GSM module so access to I2C pins is not straightforward (unless you're using a PROTO, not an INDIO).

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Answered on 4/17/21, 8:24 AM

In your test, how much time has taken the ssl channel establishment on the D21G? Thanks!

Enrico Michieletti
on 4/18/21, 7:11 AM

hi, it takes 3.7 seconds in my case, using the library example (changing Serial to SerialUSB)

on 4/19/21, 1:13 AM

Thanks! As from i've read, the crypto chip can almost halves that time. Yes, you need one certificate for every ssl tunnel endpoint (that can be more than one). I will try something. Thanks!

Enrico Michieletti
on 4/19/21, 7:19 AM

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Asked: 4/16/21, 8:10 PM
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Last updated: 4/17/21, 8:24 AM