STM32F446 - STM32CryptographicV3.0.0 and CRC use

[Thomas Chapelle]

Posted on July 20, 2017 at 14:28

Hi all

I have a function using the STM32CryptographicV3.0.0 to do AES-CMAC encryption / decryption on a STM32F446. This works fine.

I have a function 

using the CRC peripheral of the

STM32F446 

to check the integrity of the flash. 

This works fine.

My problem is when doing both at the same time or sequentially, the call of

encryption / decryption of the lib seems to use the crc and mess with my flash CRC calculation. (CRC_DR is set to 0 after the call)

In the pdf CD00208802.pdf User manual STM32 Cryptographic Library, i found out the note : 'Note: 3. CRC peripheral is used ', so i guess it's pretty normal to have this behaviour.

Is there a way to do them at the same time ? or am i forced to do a pure crc software implementation for the check of my flash ? 

[Tesla DeLorean]

Posted on July 20, 2017 at 14:53

Depends how frequently you check the FLASH.

The library tests the CRC to confirm it is using STM32 hardware, if this annoyed me sufficiently I'd remove the test.

[Imen.D · Accepted solution]

Posted on July 20, 2017 at 16:00

Hi,

Cryptolib use the CRC, so it's not possible to use CRC at the same time in Cryptolib and

check of the flash.

Imen

[Tesla DeLorean]

Posted on July 20, 2017 at 16:35

The complaint is that it doesn't need to interfere with the CRC peripheral, but does.

Does the library contain public domain, open source or GPL code?

[Thomas Chapelle]

Posted on July 20, 2017 at 16:39

Cryptolib use the CRC, so it's possible to use

them at the same time and not for the check of the flash.

Did you by possible meant IMpossible ?

The library is licensed by ST 'Licensed under MCD-ST Image SW License Agreement V2'

[Imen.D]

Posted on July 20, 2017 at 16:44

Sorry, It's a typo. I have correct my answer !

[Thomas Chapelle]

Posted on July 20, 2017 at 16:53

Alright thanks, i'll try to find a workaround but if anyone have a genius idea, feel free to share it !! 

[Tesla DeLorean]

Posted on July 20, 2017 at 16:54

 ,

 ,

Small table CRC example

 ,