Protect the code

[Luciano]

Hi,

(Copy Protection in Modern Microcontrollers).

See this link:
http://www.cl.cam.ac.uk/~sps32/mcu_lock.html

The latest paper on this subject:
http://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-630.html

Semi-invasive attacks – A new approach to hardware security analysis
Sergei P. Skorobogatov
April 2005, 144 pages
http://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-630.pdf

Best regards,

Luciano

[Darrel Taylor]

Here's some nasty little devices that can just read the protected chips without destroying them.

http://www.semiresearch.com/index.php?-1226852084
http://www.semiresearch.com/index.php?-89148003
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[Josuetas]

I thought it was almost impossible, i had read about microscopic readings of the memory and stuff like that, but this are really bad news, it even isnt that expensive!!! if you consider you could charge 5000 for one copy like DARREL already said.

So this piece of crap can copy 877A, is it safer to move to 18F?

A little thought... "had someone bought this thing? maybe its microcontroller is a 877A and we can copy it just to f...k them!" JAJAJA.

[Acetronics2]

Hi,

If you do not sleep at night ...

you can also use the Writecode function , and destroy a part of the code ... if the circuit is out of its original board !!! Not too difficult to realize ...

just a "concours Lépine" idea ...

Alain

[jason]

I have almost finished a very complicated and time consuming project. Code protection is very important to me. But I do not feel I can trust the code protect feature in the pic. so now what ?

What do you guys think of frying an IO and having a simple code that says if this io is low then erease the pic, that sort of thing ? the IO would have to goto no where otherwise the pepole who are trying to make a clone would try to find out what it is for. Normally an IO that is tied no where goes high, becuase of the internal pullup. but if we could only fry that part then it might be able to read low.

The thing is the code would need to be descrete, otherwise these copy cats would see it easy.

[RussMartin]

The subject of code protection came up in one of the classes I attended at Microchip's 2007 Masters Conference earlier this month.

According to the information I received, if the CP bit is set: So far, no one has come up with a way to beat it short of a physically invasive method--microscopic examination of the die.

Russ

[Darrel Taylor]

It figures Microchip would say something like that.

But with devices like those linked in post #4.
I'm not sure how they can keep a straight face when they do.

They keep changing they're links, so if they don't work goto

http://www.semiresearch.com

and select "Secure MCU Readers" from the menu.
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[Jerson]

The subject of code protection came up in one of the classes I attended at Microchip's 2007 Masters Conference earlier this month.

According to the information I received, if the CP bit is set: So far, no one has come up with a way to beat it short of a physically invasive method--microscopic examination of the die.

Russ

I have heard these quotes before. All I know of cracking devices is, that it's as simple as burgling a house. When you leave home, you put the biggest padlock you have on your door and bolt it down. When a burglar strikes, he reverses the procedure. The last time I read up on this topic, I learnt about using devices out of spec (power/timing) to beat various protection schemes. The power glitch is one very interesting technique and is sucessfully used by 8051 hackers. A related phenomenon is when you have the flash being corrupted by mere power on/off cycles. BTW : the Rst pin in the 8051 family usually is the VPP pin. Doesn't that say enough? I am almost sure that most flash micros are prone to this type of failure.