A low and high side isolated current sensor for side channel attacks

Isolated Balun-Based Current Sensor

Sold by Stephan Electronics

$31.54

No tax for United States [change]
a single 18650 cell holder to power the platform
Stock available: 99
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Product Overview


This board has been designed with side channel attack measurements in mind.
It is meant to be inserted inline with supply rails, either on the high or low side.
A potentiometer allows you to vary the inline resistance.


Frequency Response


The sensor frequency response for different potentiometer positions can be seen below.
From DC to 50MHz:

From DC to 1GHz:


As you can see, high frequencies get amplified the most, which will actually be beneficial in an attack measurement setup as wires will attenuate high frequencies.
The above measurements were made using 40dB of external attenuation and 45R series resistance, so the maximum current-voltage gain the platform can offer is 50.5dB or 335x.


Power Supply Setup


In side channel attacks, noise is your enemy.
In the center of the board you'll notice 0.1" header holes to solder a quiet 3.7V to 4.1V power supply source (pinout is shown at the back of the board). If you choose to solder a 18650 cell holder, rest assured the board contains a protection circuit against under/over voltage conditions.
Similarly, the power supply going to your attack target should also be very quiet.


Measurement Setup Advices


When performing side channel attacks the following rules should be followed:

  • eliminate any wires you may have, or keep them as short as possible
  • use clean power supplies (batteries, or lab PSU filtered by LDOs)
  • make sure your output isn't saturated (if so, add another resistance in //)
  • keep in mind that any connection may bring noise to your output
  • perform an FFT of your output with the platform off
  • make sure your trigger is repeatable

Required power supply


A clean power supply (between 3.6V and 4.2V) needs to be provided through the two holes in the center of the board. You may add a 18650 holder to your order in order to use a 18650 battery.


Notes on shipping


The high added cost for the 18650 cell holder is explained by the added shipping cost.
We strongly recommend purchasing your own 18650 cell holder on aliexpress.

Links to code and documentation

Documentation (limpkin.fr)

Design Files (github.com)

Schematics (github.com)

Bom (github.com)

Shipping policy

All of our devices are shipped from Shenzhen, China. It takes between 2 to 3 weeks to receive your order.

Swiss customers: please contact us directly to arrange a local sale.

The seller

Stephan Electronics

Lausanne, VD, Switzerland
77 orders since Apr 4, 2022
From the creator of www.limpkin.fr, this shop lets you buy different open hardware projects.