thoughts on one time pads

[Anne & Lynn Wheeler]

John Denker wrote:
>   One drawback with this is that you have to destroy a whole
>   disk at a time.  That's a problem, because if you have a
>   whole disk full of daily keys, you want to destroy each
>   day's key as soon as you are through using it.  There
>   are ways around this, such as reading the disk into volatile
>   RAM and then grinding the disk ... then you just have to make
>   sure the RAM is neither more volatile nor less volatile than
>   you wanted it to be.  That is, you use the disk for *distribution*
>   but not necessarily for intermediate-term storage.

is there any more reason to destroy a daily key after it as been used
than before it has been used?

one of the attacks on the stored-value gift cards has been to skim the
cards in the racks (before they've been activated) ... and check back
later to see which cards are gone.

i was standing at grocery store checkout last week ... apparently it was
the store manager ... one of the other employees came up with a gift
card that somebody had bought before xmas and gave as a present. they
had come back complaining that there was no money credited to the
account. it could have simply been an computer foul-up ... and then
again, it could have been somebody had skimmed the card, waited and then
drained the account.

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