Scratch an Imported Smartcard Chip, Find a 19 Cent Part

XBox hacker turned Chumby engineer Bunnie Huang got his hands on a microchip imported from Asia marked as an ST19CF68s, a "CMOS MCU Based Safeguard Smartcard I/O with Modular Arithmetic Processor."

He examined the chip's interior under a microscope and discovered that inside it's a completely different, and vastly less expensive, piece of electronics: a 19 cent low voltage buffer/line driver that you might pick up at Radio Shack.

Normally, remarked chips are pretty cheesy: they are sanded, painted over, or ground down before being marked, typically with just a silkscreen; rarely do you see a laser used to do the remarking.

These chips show no evidence of any kind of remarking per se. These are original markings -- someone acquired blanks of the 74LCX244 chip, and programmed a production laser engraver to put a high-quality fake marking on an otherwise virgin package. I, too, would have been fooled by this up until the chip was decapsulated and examined under a microscope.

This leaves a lot of questions unanswered. How was someone able to acquire unmarked Fairchild silicon? Was it an insider, or was Fairchild sloppy and throwing away unmarked rejects without grinding them up or clipping off leads so they can’t be dumpster-dived and resold? The laser marking machine used isn’t one of the cheap desktop engravers either -- the marks are done with a high-power raster engraver, and the engraving artwork is spot-on.

Huang writes, "If fakes of this quality become more common, this could present a problem for the supply chain." His postdetails his detective work and is chock full of awesome Silicon CSI photos.