Laser fault injection system enables smart card security testing
Protecting smart card chips and other embedded microchips against unauthorized access is one of the main security challenges facing the smart card industry.
Riscure (Delft, the Netherlands), an independent security testing lab, has been specializing in the evaluation and intensive testing of smart card and embedded chip products that are designed to operate securely in a hostile environment since its founding in 2001. With the new Diode Laser Station designed and built by optical module and system supplier Opto Sonderbedarf (Gräfelfing, Germany) in collaboration with Riscure, it is possible to perform advanced laser fault attacks that exceed the highest international standards to assess whether a smart card or other embedded chip is secured against attack.
The goal was to create a video-based, high-power microscope instrument capable of delivering and imaging an extremely small, highly focused area of two wavelengths of laser energy to localized areas of a secure microcontroller, and then to allow repositioning of the chip with very high accuracy. Competing laser setups currently used for fault injection attacks on smart cards are typically based on laser cutting technology. Diode lasers historically have lacked the power and small spot sizes necessary for effective chip manipulation. Opto based its system design on one of its high-resolution, multiport microscope platforms, integrating the laser profile coaxially into the microscope. The developers incorporated a novel adjustment mechanism into the system that enables the imaging CCD to be positioned perfectly into the laser and image path to micron accuracy in x and y directions. A customized laser-in port was incorporated into the main optical path of the microscope; a future upgrade path was made possible via mechanisms enabling switchable beamsplitters and other filters to be introduced into the laser path. The optical correction of the microscope to the the two necessary wavelengths required custom glass optimized for zero image and focus shift across the required optical bandwidth. The Riscure system also is able to control laser spot size according to user preference, with laser spot sizes as small as 6 × 1.4 μm. Sample illumination was provided coaxially, based on a long-life, high-power LED source. In order to offer maximum image contrast gains at the high magnifications required by the system, Opto incorporated its "Köhler" illumination delivery module. The Köhler principle employs a series of adjustable aperture diaphragms to create defined, parallel light rays to pass through the specimen. According to the company, this results in significantly increased image contrast enhancement at magnifications of 20x and higher. At the front end of the system, a rotating objective turret was fitted with three long-working-distance near-infrared (NIR)-optimized microscope objectives offering 5x, 20x, and 50x magnifications. -- Posted by Vision Systems Design
