(Disclaimer: Smart card piracy is a very bad thing. This set of blog posts is NOT intended to further illegal hacking of paid services, but is merely a personal record of my research, which is not being done for any financial reasons but is only done for personal leisure. Besides, these cards won’t help you break scrambled TV signals, so don’t bother trying it :))
In between pulling all-nighters
goofing off doing college homework and trying to stay marginally sane and/or healthy, I’ve been doing some more research into the cards. This time, I was a bit more invasive with my approach. However, I’ve found out a bit more about the card’s brains this way.
I’ve torn open one of the cards and taken a peek inside. The chip itself is a bit different in that the epoxy backing is molded much like a regular chip as opposed to the drop of epoxy used in many newer cards. The chip itself is pretty big, at 6mm x 4mm and with 0.1 mm thickness; the center gold pad is the entire area of the card.
There are many methods of getting the plastic off of a chip, and the more professional labs use fuming nitric acid (very nasty stuff) but one easy way to do so at home is using a blowtorch to burn the epoxy and simply chip it off with a toothpick. If it’s burnt thoroughly enough, the epoxy will just fall off the chip, revealing the pretty silicon underneath. I used a small butane torch to heat up the chip, which was done outside and on a piece of ceramic tile (safety first! :)) After a bit of picking at the chip, I was able to see the inner workings of the smart card’s chip.
I see 4 large blocks on the die but can’t tell much more without a microscope, and a 10x jewelry loupe only goes so far. My best guess is that the 4 blocks encompass the CPU, RAM, program ROM and maybe some EEPROM storage. There’s 14 pads on the chip; 5 pins are used for the contacts, maybe 2-3 for the radio interface, and the others might be for factory testing or programming but it’s speculation at best.
Now hopefully my college prof won’t mind me using the classroom microscope later this week 🙂