Flowcode Support Board

I found the esp32 datasheet (at https://www.espressif.com/sites/default ... ual_en.pdf ) - which makes for interesting reading.
I managed to get the 'genuine' random number generator working easily but - as I need SHA256 function for a project - then tried to get that working by writing to registers / memory (it looks straightforward!)

This failed - always returning 0.

So then - trawling through the espressif includes found mbedtls/sha256.h - which does exactly what's needed (other SHA schemes are also available!)

I wrote a simple program to test - and all seems well. It can probably be made into a component too. Here it does a very simple SHA256 calculation (4 bytes) - and I checked the result against https://xorbin.com/tools/sha256-hash-calculator (which doesn't need quotes)

Note that you can amend the mbedTLS config by using idf.py menuconfig (it's under component config).
SHA256_Update takes an array of bytes of any length and can also be called multiple times before calling SHA256_Finish.
I don't check the result bytes returned (0 is success)
There are a host of other 'tools' in the mbedTLS folder (sha512, RSA etc) which look similar to use....

Martin

Hi Martin

Although I've no need for that functionality just yet, it's always interesting to read your "how to" posts.

Regards

mnfisher wrote: ↑

Wed Nov 01, 2023 6:50 pm

It can probably be made into a component too.

Thanks mnfisher!

Any component would be nice!
I look forward to it!