OT-SCA Capture Scripts

The caputure_*.py scripts provided in this directory allow the user to capture traces of a cryptographic operation performed by OpenTitan.

Quick Usage

Follow the steps described in the getting_started documentation to setup the environment, the target, and the scope.

When using OpenTitan on the CW310 and measuring traces using Husky, AES traces for a random key tests can be captured with the following command:

mkdir -p projects/
./capture_aes.py --capture_config configs/aes_sca_cw310.yaml --project projects/aes_sca_cw310_random

The traces are then stored in the database file in projects/.

If the ChipWhisperer version check fails, please update the Python requirements:

pip install -r python-requirements.txt

When the ChipWhisperer Husky firmware version check fails, update the firmware:

./util/update_husky_fw.py

Make sure that you have the USB permissions. If the update fails, follow this guide.

Capture Config

The capture configs stored in configs/ follow the following structure:

• target
• scope type (husky or waverunner)
• capture
• test

The target entry specifies the target. Currently, only the cw310 or cw305 FGPA boards are supported. The scope entry defines (indirectly) the sampling rate as well as the scope gain and cycle offset. With the capture entry, the user can select the corresponding scope, configure the trace plot, and select the trace database format (either chipwhisperer project or OT trace library in the SQLite format). Test provides different entries for the cipher config.

Adding new Cipher Capture Scripts

To add new cipher capture scripts, please use the caputure_aes.py script as a template. The template follows the following structure:

• Setup the target, scope, and project
• Configure the cipher and establish the communication interface
• Capture traces
• Print traces

The communication interface (e.g., the individual simpleserial commands) for each cipher needs to be added to lib/ot_communication.py.