Re: Cryptoengines with usage accounting

From: Anne & Lynn Wheeler (lynn_at_garlic.com)
Date: 09/10/03 

Date: Tue, 09 Sep 2003 23:26:22 GMT

"Ernst Lippe" <ernstl-at-planet-dot-nl@ignore.this> writes:
> I know that at least one electronic purse (Proton) had an option to
> maintain an audit trail of the most recent transactions. But apart
> from that, I have never seen any kind of auditing in Smart Cards or
> HSM's.
>
> There is a good reason to avoid such a feature with Smart Cards. The
> memory contents of a Smart Card can only be rewritten a limited
> number of times and a counter that is frequently updated will reduce
> the life span of the cards.

there used to be all sorts of hoops jumped thru, technology, and
patents around minimizing number of writes to EEPROM .... a lot of
chipcards used EEPROM-based memory to maintain charge when there is no
power ... most chipcards operate with out any sort of battery ... and
7816 smartcards draw their power from the contacts when inserted into
reader ... and 14443 (contractless) smartcards draw power from the air
when they are in proximity to a reader.

the late '80s and early '90s chips had no good random source and used
EEPROM that had duty cycle in 10k writes to 30k write range.

you can get chips these days that have duty cycle with EEPROM rated
for 800k writes and above. At hundred uses times per day and ten
writes per useage, or thousand writes per day ... that has life cycle
over two years. Using it five times per day and even ten writes per
useage gives life cycle over forty years. Historically, getting writes
down to one or two per useage and five uses per day ... increases life
cycle to over 200 years.

aads chip strawman
http://www.garlic.com/~lynn/index.html#aadsstraw
& instantiated
http://www.asuretee.com/

slightly related (trusted hardware token reference towards end of post):
http://www.garlic.com/~lynn/aadsm15.htm#6 

-- 
Anne & Lynn Wheeler | http://www.garlic.com/~lynn/ 
Internet trivia 20th anv http://www.garlic.com/~lynn/rfcietff.htm

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