STM32 crypto on microSD with PC deciphering

[FCont.1]

I am working on STM32u585. The STM receives data on SPI bus, cipher data and store cipher data on microSD.

Then the microSD is read on PC and data has to be deciphered for human reading.

What is the best mean to perform this ciphering process ?

Can the data on microSD be deciphered easily on PC ?

Thank you.

[KnarfB]

There are too many unknown variables in your description to nominate a winner. Like: key management (among users, devices, ...), amount of data to encrypt, etc..

Looks like you have to do a due diligence here.

hth

KnarfB

[Tesla DeLorean]

It is just data in a file, surely reading and writing a data stream to a file is a 101 level topic.

Don't use a custom format for the file system, use FatFs and manage the crypt task at a file level. A file after all is just a collection of bytes.

Are you going to use a standard cipher, and data format?

Can you write PC side applications yourself, or within your team?

How strong or computationally cheap does the encryption need to be?

Symmetrical or Asymmetrical?