Chip Obfuscation - why? - Page 1
Forum section: electronics / projects

author: ArthurGuy
author_rank: Newbie
timestamp: January 21, 2014, 12:33:23 pm
content: Hello all,I recently dismantled a camera light and the 3 ic's all had the serial numbers ground off, I am guessing this is to help stop the design being copied by another manufacturer but I was wondering if anyone knows for sure?The video below shows the ground off markingshttp://youtu.be/RV4-8UDbS48?t=10m27sThanks,Arthur

author: digsys
author_rank: Unknown
timestamp: January 21, 2014, 12:43:19 pm
content: Some do it for that reason. Usually it's not hard to work out what the ICs are, especially if you have a DSO.Many are copies themselves, and they don't want the people they copied off to easily check. The only time is may "slow down"a copier, is if the IC is custom, or very "rare". It's a pointless practice these days, with the great www

author: ArthurGuy
author_rank: Newbie
timestamp: January 21, 2014, 12:54:09 pm
content: Thanks for the confirmation

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 21, 2014, 01:05:25 pm
content: It's basically done by manufacturers who are so stupid or unimaginative that they don't understand that it makes little difference to anyone who is seriously trying to copy it, unless it's an extremely obscure chip.Most of the time it just makes them look like a bunch of amateurs.

author: dannyf
author_rank: Super Contributor
timestamp: January 21, 2014, 01:15:13 pm
content: QuoteQuoteGood answer.

author: grumpydoc
author_rank: Super Contributor
timestamp: January 21, 2014, 01:20:32 pm
content: It makes repair harder or impossible for third parties - this might be important to manufacturers who really want you to buy the latest toy, not get an old one fixed.

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 21, 2014, 02:04:06 pm
content: I'm guessing it's a misguided attempt to deter copying of the product. I worked on a product where we removed the labels from the in-panel meters as one step to prevent casual copying and/or repairing.But ultimately it's misguided. Either someone is trying to fix the darn thing and wants a replacement chip, or they want to copy it. In the former case, you're just making it frustrating, and in the other, it will do nothing at all to prevent diligent transcription of the circuit design and eventual identification of each chip.

author: dannyf
author_rank: Super Contributor
timestamp: January 21, 2014, 02:17:20 pm
content: QuoteSanding the chip does nothing to prevent some from figuring out the schematic - though a multi-layer pcb will do wonders there.However, even with the schematic, it can be difficult to identify a chip, even if you know the general categories of the chip. To make the identification more difficult, you can randomly tie unused pins to Vcc or GND. It does wonders there too.

author: Kjelt
author_rank: Super Contributor
timestamp: January 21, 2014, 03:15:53 pm
content: You can see that this method sometimes still works at the huge number of "who can identify this chip" topics where even normal smt components with their official markings can not be foundAnyway, even HP used this method by using their own codes on OEM chips but probably more for logistical reasons then obfuscation reasons and although a lot of chips can easily be identified (esp. uControllers with their manufacturer specific osc inputs and outputs) it could be a hurdle for the somewhat less devoted of copiers.

author: dannyf
author_rank: Super Contributor
timestamp: January 21, 2014, 03:43:32 pm
content: Agreed. Just because something may not be effective sometimes doesn't mean it is not useful, or worse yet, incomprehensible.

author: Kjelt
author_rank: Super Contributor
timestamp: January 21, 2014, 03:51:29 pm
content: It's the same with security engineering, everyone in that field knows that obscurity should never replace security, meaning that you can not rely on obscurity alone to make something secure.But it can make the life of attackers a lot more difficult if they also have to find out which encryption scheme you use, what the protocol (fields, values, ranges) exactly are etc. etc. No firm that has a security protocol in place will provide that on their website.

author: dannyf
author_rank: Super Contributor
timestamp: January 21, 2014, 04:08:38 pm
content: Totally agree. The goal isn't really to foil every thief: you just need to discourage the thief sufficiently so s/he takes the next victim somewhere else.For that, a less-than-100% effective approach can be effective.