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ChipWhisperer Lite, USB Fun

A project log for ChipWhisperer®: Security Research

ChipWhisperer laughs at your AES-256 implementation. But it laughs with you, not at you.

coflynn 11/14/2014 at 15:030 Comments

For a while now I've been planning the low-cost version of ChipWhisperer, which I call 'ChipWhisperer Lite'. The idea is to integrate everything onto a single board, and use a lower-cost FPGA (Spartan 6 LX9 instead of LX25). Some features will have to be dropped (such as the SAD trigger) to fit this device, but for most users it'll be perfect. I also plan on bringing this hardware with me for the training course I'll be running.

Here's a quick screen-shot of the basic PCB parts placement. The right half is the 'Target Board', which will be a break-away from the capture hardware (left half):

One of the more interesting aspects of the design will be the change of USB interface chip. To keep costs down I'm not using the Cypress EZ-USB chip. Instead I'll be using a Atmel SAM3U, and providing my own firmware. I'm hoping to publish the firmware for use in other projects - lots of people want high-speed USB connectivity for their FPGA project. I think this can be made into a nice generic solution, and will be cheaper than anything else (including the FTDI FT2232H).

I've got a SAM3U-EK dev-kit which I've done some experiments on, and it seems to be 'sufficiently fast'. It won't be as high-bandwidth as the EZ-USB solution which can almost max out the USB transfer bandwidth, but considering that this board doesn't have on-board SDRAM, that won't be an issue (not as much data to transfer!).

As a side-note: I've got some longer-term plans to release a whole bunch of USB firmware solutions for low-cost chips. Both Atmel & Microchip make some nice USB microcontrollers which are very low-cost - with the right firmware they could be turned into USB-Serial, USB-Parallel Port, USB-Keyboards, etc. But back to the project at hand:

Current estimates of the BOM cost are about $100 in single-unit quantities (the analog portion alone is ~$40), so would expect to sell around $300 (BOM x3 is fairly reasonable estimate). But this version won't have BGA parts - all TQFP (albeit small pitch), so it should be well within the realm of 'hand assembly' possible. This will make it the lowest cost version available by a long shot, and I really want to keep a version of this hardware at the "hand-assembly" level.

I also appreciate all the kind remarks about this project getting second place for HaD Prize too! It's been an honour to make it so far in the face of such intense competition, and having seeing a *lot* of the other cool projects that were involved (beyond just the final five), I was very pleased with those results. It's been a fun ride of course, but lots of work still to do, so no time to rest yet ;-)

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