TM4C123 AES encryption

You may need to sign some sort of undertaking not to export or not to export to certain areas.

Robert

Hello Dan,

The ROM tables in TM4C123 are not hidden from application software and hence using the same would be something I would not suggest.

AES software algorithm are available on the web by a lot of folks, but such computation are CPU resource intensive. The HW AES of TM4C129 does this far more efficiently as shown in wolfSSL benchmarks.

Regards
Amit

Hello Amit,

why you would not suggest using the TM4C123 ROM tables for AES? Are there plans to remove them in further revisions?
AES libraries which makes use of them are still available form stellaris times. This approach would save me some words in my crypto code for bootloader usage. HW AES might be overkill for my application (in the past I used a software approach for AVR).

Thanks
Dirk

Hello Dirk,

If you have the code from earlier Stellaris Devices then it should work as is. However the decision on doing an example code with the same is still pending.

Regards
Amit

Hello Amit,

thanks for your reply. It looks like it's a legal or strategic decision and has no technical reason using these functionality.

Regards
Dirk

Hello Amit,

thanks for your reply. It looks like it it's a legal or strategic decision and no technical cause.

Regards
Dirk

Hello Dirk

I have asked the team to look into it. Hopefully should hear from them in a few days.

Regards
Amit

Hi Amit,

Has their been any movement on the AES in the Tiva 123x?  I am looking to see how many bits the hardware implementation provides (128 / 256) and also see if there is sample code (sounds like just the older Stellaris code is available).

Also, is there any ECDH implementation?  Do we have any source we could point them toward?

Best Regards,

Blake

Hello Blake

No, there is no ECDH implementation for TM4C family of devices

I figured as much, but found a software implementation easily as you suggested above. Are the tables AES 256 or 128?

Thanks!

Hello Blake

Since the ROM AES Table are not provided for the TM4C123 devices, I am not sure why it would matter if the AES table for 256 or 128 bit.

Hi Amit,

It appeared that there was no hardware assist, but that there were ROM tables, but it was unclear whether these would be used with an AES128 or 256 implementation.  

Sounds like we should use our own software and ignore the ROM tables completely?

Blake

I did some looking at the AES wiki page, and it appears that the Key length is the difference between 128 and 256, but from a casual look, it would appear that the AES algorithm tables would work with 128, 192 or 256 bit key lengths.

I see there is no tivaware driver so it looks like I will need to pull the software code from someone like mbed off the web.

Best Regards,

Blake