How to write 4096-byte data based on AES CW305 example

[ruka]

Hi, I am currently modifying the CW305 AES example and trying to load a full 4096-byte buffer into my design in one operation. My goal is to capture power traces duing the processing of this entire 4096-byte sequence, rather than sending one 16-byte AES plaintext block at a time.

I would like to ask: what is the recommended way to import a complete 4096-byte data buffer into the CW305 design without heavily modifying the existing AES example?

I’m using a Husky as the capture device, and both the Husky and CW305 firmware are up to date.

I found a similar thread on the forum but with no solution yet. Any advice or pointers would be greatly appreciated!

Can't write 64 bytes with fpga_write in AES example

I’m modifying the AES CW305 example, and one thing I’m doing is increasing pKEY_WIDTH to 512. However writing to target.REG_CRYPT_KEY doesn’t seem to be working with target.fpga_write(target.REG_CRYPT_KEY, cw.util.CWByteArray(<my 64 bytes>)[::-1]) and target = cw.target(scope, cw.targets.CW305, bsfile=<my bitstream>, force=True, fpga_id=fpga_id, platform=platform). Working back through the repo, this seems to be calling (in software/chipwhisperer/hardware/naeusb/naeusb.py via software/chipwhis…

[jpthibault]

Yes, there is still an issue here. We will try to get that fixed soon.

Once it’s fixed, supporting larger registers is simply a matter of defining pBYTECNT_SIZE appropriately. This is explained here: https://media.newae.com/appnotes/NAE0010_Whitepaper_CW305_AES_SCA_Attack.pdf

BTW are you sure you’re looking at 4096 bytes? If so be sure to implement the associated storage as BRAM, otherwise it will use up a very large portion of the FPGA’s LUTs.