[Cryptography] Magnetic media destruction question

[John Levine]

It appears that Christian Huitema <huitema at huitema.net> said:
>> Are there any security standards that mandate beyond-DIN 66399 T-7 shredding?
>> And what threat modelling is being done that would imply someone can recover
>> data off a piece of confetti buried in among a million others?
>
>It is certainly possible to put back together shredded documents from 
>the confetti. 

T-7 is about shredding magnetic media, not paper.  I don't see what relevance that has.

The spec says that T-7 shreds magnetic media into chips no larger than 2.5mm².  I agree
that it seems implausible that one could recover data from those.

The paper they recovered was probably P-1 or P-2, strips 12mm or 6mm wide, which is a
lot bigger, and of course you can see what's on the paper.

R's,
John