Em 12/2/2010 06:52, Alan B. Pearce escreveu:
>>> But you are missing the point. By making the ICSP connection available,
>>> by bringing out the PGM connection, then anybody can do anything to the
>>> code in the devices you are producing.
>>>       =

>>
>> No way! If the part is code-protected, the only thing one can do is to
>> erase the part. After erasing then he can do whatever he wants (program,
>> debug, read, etc.), but the original firmware/bootloader will  not be
>> there anymore.
>>     =

> Exactly, but why make it easy for someone to do this, and potentially dam=
age =

> the reputation of your company by loading your device with rogue code?
>
>   =

>>> By having a bootloader it is possible to set most chips up so that the
>>> bootloader is protected against erasure, and it ensures that whatever
>>> does get downloaded is from a controlled source. The bootloader can only
>>> be erased if the PGM connection is brought out to the outside world.
>>>       =

>>
>> Even if you cut the ICSP pins close to the package, somebody could
>> scratch the plastic to solder some wires to them. He could even unsolder
>> the chip and buy a new blank one.
>>     =

> Agreed, but why make it easy for them, by having all the connections open=
ly =

> available?
>
>   =

>> It is not possible to ensure that nobody will damage the equipment or
>> erase the firmware. What you should be worried of is to protect the
>> intellectual property inside it. If your customer damage the equipment,
>> lucky you, he will need to buy a new one.
>>     =

> Well, there are two points here. One is if someone damages the item to a =

> point where it doesn't work any more then you get to sell them a new one. =

> Great, more money in your pocket!
>
> But if you make it easy for someone to reprogram your device, by making a=
ll =

> the ICSP connections readily available, then you stand a good chance of =

> having your product reputation damaged by someone loading your product wi=
th =

> code that does rogue things. Your product looks totally undamaged, comple=
te =

> ex your factory, but doesn't perform to your specification. It is YOUR =

> reputation that gets bad mouthed, and you sell less because of it, not mo=
re. =

> The problem then is that the reputation gets carried over to any other =

> product you produce ...
>
> There are enough hackers out there that seem to figure this is their job =
for =

> life, that making it easy for them to do so is stupid.
>   =


Perhaps I'm mistaken, but I think that of the people trying to crack MCU
chips, 99.9% are trying to steal the code to make pirated products. The
only thing they may want to change are some displayable messages like
brand name or product model, to sell the product as if they created it.

The perhaps 0.1% of them that have some interest in modifying or
creating a different firmware for an existing product are trying to
adapt the product to their own needs, not trying to make your product
seem defective. I think they are mostly hobbyists and DIY guys, that are
not going to blame you for changes themselves did.


Regards,

Isaac

__________________________________________________
Fa=E7a liga=E7=F5es para outros computadores com o novo Yahoo! Messenger =

http://br.beta.messenger.yahoo.com/ =


-- =

http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist