topic Re: mmCAU library, AES Initialization vector in Kinetis Microcontrollers

mmCAU library, AES Initialization vector

emilien — Wed, 12 Sep 2012 10:24:09 GMT

Hi,

I'm using the mmCAU library, and I'm able to run cau_aes_set_key, cau_aes_encrypt, cau_aes_decrypt with a 16bytes key. It worked and I could retrieve the original plaintext on my Kinetis K60. However, the documentation says it's CBC and I don't get how the Initilization vector is picked (This I cannot decrypt on my desktop when I receive it from the network)

Where can I set this initilization vector ?

I'm using "CAU and mmCAU version 2.3".

Best regards,

Emilien

Re: mmCAU library, AES Initialization vector

emilien — Wed, 12 Sep 2012 14:53:08 GMT

Hi again,

I've figured out it's not CBC mode, but ECB mode which is used in the mmCAU library... which is weird because in the AN4307 I can read "All the crypto algorithms are executed in Cipher-block chaining (CBC) block cipher mode to increase block encryption and decryption security". Any idea about how to use CBC? Anyway I guess until nanoSSL comes with a Kinetis implementation, I have only poor encryption solutions...

Re: mmCAU library, AES Initialization vector

PaoloRenzo — Thu, 20 Sep 2012 21:17:00 GMT

Hi Emilien

mmCAu library implements ECB mode (no initialization vector). AN4307 implements CBC wrapping mmCAU libray for this feature. You can get more details in AN4307SW.zip from freescale web page:

Go to:

K60_100 Product Summary Page ---> Run-time Software (18) ---> Lab and Test Software (1)

More details here:

Block cipher modes of operation - Wikipedia, the free encyclopedia

Hope this helps

Paolo

Re: mmCAU library, AES Initialization vector

edwardcullen — Wed, 25 Sep 2013 10:06:46 GMT

Hi Paolo, I need AN4307SW.zip to implement mmCAU in my thesis.I followed your instruction to get software AN4307 but require some info :"Export Compliance Project Inquiry", and I also provided info about my project but I haven't received Freescale's answer yet. Could you help me ?