How to "open" a microchip and what's inside?
zeptobars.ru
zeptobars.ru
After you get the images of the metal layers (you likely can't do this optically for things down near Metal1) you can image the poly and diffusions. You can probably guess which transistors are which based on which power rails they would have been connected to.
Things might be easier if you know what standard cell library the designers used when laying out the chip, as then you'd more easily be able to identify the base logical functions faster.
If you're being thorough you'd also have to make sure you obtain measurements of the widths of each of the transistors (so you can later figure out the relative drive strength which matters for things like identifying keeper circuits or more precision analog elements etc).
Determining some transistor behavior make require even more complicated tests to identify doping levels and if you were trying to duplicate the process you'd have to identify a large number of other materials (for example if they use copper you'd want to find what chemical they used to control the diffusion etc).
It's pretty interesting stuff though.
Reverse engineering Digital can be conceivable by looking at blocks, but for analog it can be incredibly difficult.
I am still looking to find soviet 286 (КР1847ВМ286), but it seems it is extremely rare. If anyone have one - contact me ASAP :-)
Just to be fair - I didn't find that soviet "clones" were clones - layout was changed significantly. Centralized planning demanded 100% compatible chips to make near-100% compatible computers, that's the root of all evils.
I've always wondered how people map chip-die photos into something like this: http://chip-architect.com/news/2007_02_19_Various_Images.htm...
or this: http://chip-architect.com/news/2003_09_21_Detailed_Architect...
I can see how figuring out the cache and the internal buses might be doable, but the rest... Any insights?
Also, there are a few collectors over here: http://www.cpu-world.com/forum/
Maybe they can get you a lead on one.
Never knew a microprocessor/microcontroller/ASIC could be reverse engineered.
How do they even tackle such complexity?
Do you know of any resources which explain how it is done?
There is also software for automatic photo->schematics conversion, but this is quite complicated & not something you can buy at store.
You're right, it's too cool for stores.
I've got things started with the 74HC595 die photo at [3] and [4].
[1] http://zeptobars.ru/en/contacts
[2] https://commons.wikimedia.org/wiki/Commons:Licensing#Well-kn...
Visual 6502 for taking such photos and then emulating, or should I say simulating, the cpu from the images - in JavaScript: http://visual6502.org/
Chipworks for commercial silicon analysis of big modern system on chips (source of some photos of recent apple silicon): http://www.chipworks.com/blog/technologyblog/2013/01/21/the-...
Is it at all possible? On what kind of budget?
Say there's a number hidden on a modern CPU chip, a cryptographic key. That's one of the things "Trusted Computing" architecture uses, right? Is there any way to retrieve that key? With a really large budget? Or is it truly impossible, tamperproof beyond any macroscopic objects, not accessible without destroying the data itself?
Because if that is so, that'd be disgusting, and I understand one of Richard Stallman's paranoid precautions quite a bit better--afaik the netbook he uses has one of the few brands of chips whose design is "open". Of course if it's tiny enough, you still don't know if what's in it is exactly what the design says should be in it (like running binaries instead of compiling from source), but I suppose that is the best one can do.
It's crazy then, that with our drive for faster and faster computers, at some point, we may lock ourselves out.
Cloning whole chip is probably economically not viable, but definitely possible (it's cheaper to design from scratch with modern automatic design tools), but retrieving secret keys is a popular task.
For a company having all the tools (electron microscope with bells and whistles, polishing machines, microprobes) it might take hundreds to thousands of human-hours (0.1-1+ million $).
Companies like http://www.chipworks.com/ can do that, if your request is legal.
It's certainly doable to reverse engineer out a cryptographic key from a chip, but most of the people who could afford to do this wouldn't really need to do so. Secure elements are typically substantially more protected than standard logic. The structures can be designed in a manner to be very difficult to access without damaging them rendering them unreadable.
Such a cryptographic key would likely be scattered in pieces around the chip, delivered through winding busses below enough critical logic connections and power rails so that the chip wouldn't be as vulnerable to a focused ion beam attack or infrared analysis. This makes it difficult to observe without destroying enough of the chip that live examination would not be possible. There are also tricks that would be used to mitigate the risk of differential power attacks etc.
The bigger threats to secure elements are sloppy design with DFT/DFM (Design For Test) features. Most complex chips have at a minimum a mechanism of connecting a large number of the designs flops to what's like a huge shift register. If you knew enough of the design you could try to locate the output of a block which has access to the secure value, scan in a vector that makes it easy to recover the value (e.g. an XOR element you can force to XOR with 0's) and scan it out.
There are also other DFT feature like on-die logic analyzers, micro-breakpoint engines, code signing overrides etc. Virtually all of these features are physically disabled prior to volume manufacturing. If a company was sloppy this could expose things that shouldn't be exposed.
There are other attacks as well though. If you could compromise the signing keys for the microcode delivered to a processor like a modern x86 processor you could change the behavior of instructions. With custom microcode you could catch and override basically any instruction (for example you could change where a LOAD instruction stores data or make ADD do jmp etc). You could definitely use something like that in a malicious manner.
Ions are charged atoms. In Vacuum you take a small inlet of gas (only very little), or heat up a small piece of solid until it evaborates, depending on what type of atom you want to use. Then ionize it (e.g. having a white glowing hot piece of wire in the vincinity) then accelerate it. With electrodes and coils (like, e.g. used in old CRT TVs/monitors) you can form have a narrow, focused beam you can move around. This all has to be done in vacuum, because the beams will stop in (dense) air immediately.
This is your "cannon" with which you can very precisely aim and shoot at a target.
Where is this done?
The microscopes used for the very delicate structures in modern microchips are normally electron microscope (not using light but electrons for imaging). They operate in a vacuum which is very handy, because in that vacuum the focused ion beams can operate.
If you want to buy, ask your dealer for a "Focused Ion Beam Workstation", e.g. http://www.photonics.com/Article.aspx?AID=50359. Have 100k€ - 1M€ to spend. ;-)
What to do?
So you have your chip in your electron microscope, and you know that buried below some other structure is a signal hidden from plain view (maybe on purpose on a secure chip, but maybe you are debugging your own design and it just happens that this is where you suspect the answer to why the chip is not operating as required).
So you set your ion-beam to "heavy noble gas, e.g. Xeon" and shoot particles to drill a small hole until you have a trench down to the interesting signal. But that trench is not wide enough to allow your (huge!) probe needle to contact. You you switch to "deposit metal" and, with much less impact velocity for your particles, like with a small brush, you put in a conductive trace from within the trench to some part on the (still intact) silicon-dioxide protective layer on top of the chip. This is where you put your probe needle that can then access the buried signal.
Attacking modules instead of chips is a little harder, especially because the modules themselves are more expensive, so expending hundreds of them in early testing is more expensive. But, for a national organization, totally feasible.
If you really want trusted computing, you need defense in depth; the devices need to be in a semi-trusted environment, so a theft/tamper event can be detected, and keys revoked, within the attack window. So, it's ultimately not possible in a feasible way for consumer-possessed devices (trusted computing for DRM); OTOH it works great in a server environment (if someone breaks in, you just invalidate all keys in the facility within a few hours).
HSMs (which have more active tamper response) are a lot better than TPMs (which are purely passive). You could probably trust an HSM even if it falls into enemy hands, unless the enemy is the HSM designer or NSA, for less than $50mm. The problem is there's no decent HSM for less than about $15k now (Thales/SafeNet duopoly). And HSMs have had implementation bugs in the past.
The process gives it an artsy mechanical feel, as if we could see the sign of time and efforts these little things put in computations.
http://www.amazon.com/Core-Memory-Visual-Vintage-Computers/d...
In the current copyright environment, I'm not sure they could be made available. Which stinks, as just looking at them & trying to figure out what the sections did (ALU, cache, registers, etc) is sort of inspiring.
Intel, AMD, Freescale, etc. should partner up with art.com or someone else who can print out large posters (and ship them wrinkle-free) Maybe donate any profits to a engineering-for-teens program of some kind.
They are called integrated circuits because, instead of using a board to connect many pieces of silicon, a single piece of silicon has the whole circuit. More at the usual place, http://en.wikipedia.org/wiki/Integrated_circuit