topic Re: HSE AES182 encryption not working correctly in S32K

HSE AES182 encryption not working correctly

Rmpr — Mon, 05 May 2025 13:10:49 GMT

Hello, I'm trying to encrypt an array of 16 of a plain text:

uint8 Data_au8[AES128_ECB_PLAIN_TEXT_SIZE] = { 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };

With the array initialized like this, this works fine since it gives the the following encrypted array:

But, this is not what I want my code to do, I want to change the values of the array in my main function, but If I do this:

uint8 Status_u8 = 0x01u; uint8 Data_au8[AES128_ECB_PLAIN_TEXT_SIZE] = { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 }; int main() { Data_au8[0] = Status_u8; Data_au8[1] = Status_u8; /* Encryption */ }

It doesn't encrypt properly:

What could be causing this?

Thank you in advance!

Re: HSE AES182 encryption not working correctly

lukaszadrapa — Tue, 06 May 2025 07:48:55 GMT

Hi @Rmpr

This sounds like data cache issue. All the data objects used for communication with HSE must be forced to non-cacheable memory. The data cache is usually configured to copy-back mode and HSE can't see the data cache on core(s), so this may cause coherency issues. HSE always accesses physical addresses only.

For quick test, you can try to disable the data cache completely. Either in your project settings or in your debugger:

Regards,

Lukas

Re: HSE AES182 encryption not working correctly

Rmpr — Tue, 06 May 2025 08:36:51 GMT

That solved the problem.
Thank you!