File Formats
File Formats (Projects and Traces)
This page explains some of the file formats used in the ChipWhisperer Software.
Project Files
Project files are stored as a simple text-file. The most basic file will include information about stored traces, along with some basic project file information.
As an example, the following shows a simple project file named "test_cw305_artix100_10k_4seg.cwp":[Trace Management]
tracefile0 = test_cw305_artix100_10k_4seg_data\traces\config_2016.05.15-18.21.25_.cfg
enabled0 = True
tracefile1 = test_cw305_artix100_10k_4seg_data\traces\config_2016.05.15-18.26.48_.cfg
enabled1 = True
tracefile2 = test_cw305_artix100_10k_4seg_data\traces\config_2016.05.15-18.32.03_.cfg
enabled2 = True
tracefile3 = test_cw305_artix100_10k_4seg_data\traces\config_2016.05.15-18.37.27_.cfg
enabled3 = True
[ChipWhisperer]
[[General Settings]]
Project Name = Untitled
Program Name = ChipWhisperer
Project File Version = 1.00
Project Author = Unknown
Program Version = V3.0
[Trace Management] section. These contain links to the trace data stored in the project. The specific link is to a configuration file, which is described below.
Normally, in the same folder that the .cwp file is located will be a folder with the same suffix. For example if you have a file called supersecret_aes_test.cwp, there will be a directory called supersecret_aes_test. This directory will contain the trace data along with additional files generated during analysis. Note it's not required that all files are located in this directory, as you can reference another location.
Trace Files
Trace files in the ChipWhisperer software are defined through a configuration file, with the suffix .cfg. Any trace added to the ChipWhisperer project will have a configuration file - this file does not store data, but tells the software where it is stored and what format it is stored in.
While ChipWhisperer has a "native" file format, you can also interface to existing files. We'll first look at the configuration file before exploring the various trace file formats supported.
The most basic trace file configuration has this format, for example this file isconfig_2016.05.15-18.21.25_.cfg that was referenced earlier:[Trace Config]
numTraces = 2500
format = native
numPoints = 240
prefix = 2016.05.15-18.21.25_
date = 2016-05-15 18:21:25
scopeSampleRate = 0
notes = ""
scopeName = ChipWhisperer/OpenADC
scopeXUnits = 0
targetSW = unknown
targetHW = ChipWhisperer CW305 (Artix-7)
scopeYUnits = 0
| Option Name | Option Description | Format |
|---|---|---|
| numTraces | Number of traces contained in this reference. | Int |
| format | The format used to store the traces. | String |
| numPoints | Number of samples (points) within each trace. | Int |
The remaining options are used to populate the "trace manager" window.
Let's now investigate specific options for the "native" file format, along with format information.
Native File Format
Specific options for the native file format are:
| Option Name | Option Description | Format |
|---|---|---|
| prefix | Prefix for the files (trace, textin, textout, etc) | String |
The prefix declares specific files. For example the prefix in the above example is 2016.05.15-18.21.25_, which means data files will start with 2016.05.15-18.21.25_.
The suffix for data files comes from the type of file, given in this table:
| File Suffix | File Description | File Type |
|---|---|---|
| keylist.npy | List of encryption key used for each trace. If the same key is used for each trace, will be the same key repeated N times. | |
| knownkey.npy | If same key used for all traces, contains the encryption key. | |
| textin.npy | Input data for each trace (i.e., plaintext if encryption). | |
| textout.npy | Output data for each trace (i.e., ciphertext if encryption). | |
| traces.npy | Power measurement for each trace. |
Each of these is a NumPy array, where the first element is trace n=0, the second is trace n=1, etc. You can load this file using the NumPy load command.