grinding down chips was Re: QX10 graphics board

[Gordon JC Pearce]

Philip Pemberton wrote:
> In message <3.0.6.16.20060127101019.441734dc at pop-server.cfl.rr.com>
>           "Joe R." <rigdonj at cfl.rr.com> wrote:
> 
> 
>>   You'd probaly better with battery backed RAM that would lose it power
>>(and contents) when it was removed from the circuit. Or else redisign and
>>use a PAL or some form or programmable logic that has a security fuse to
>>prevent it from being read.
> 
> 
> Problem is, SRAM has this annoying tendency of storing data for a really long
> time if it's frozen beforehand.
> It also tends to "remember" data bits that have been stored in the memory
> cells without any writes for a long time.

That's why the encryption cards banks use for ATMs detect when they get 
below a certain temperature, and overwrite the RAM.

Gordon