REPOST: Re: secure accumulator?

From: Jean-Luc Cooke (
Date: 10/27/05

Date: 27 Oct 2005 15:25:20 GMT

More on the attack model would help:
 - is this for software running on your computer or a potnetial
   attacker? ie. "limit # of uses for a free demo of software"
 - is this for a senario of "limit the number of times a
   software/document can be extracted/installed"?
 - Often it's best to have most of this accumulator logic running on a
   system you can have control over.


mark r. <aztxt-22@obfuscate.yahoocom> wrote:
> Hello:

> I am trying to implement an accumulator in my application to count the
> number of transactions. Are there some best-practices for building something
> that is tamper-resistant, non-refutable, and holds up against a replay
> attack (e.g. if I encrypt the string "24 transactions as of 29-OCT-2005,"
> how best can I stop someone from restoring that string every day?).

> Thank you for any best practices or referrals.

> /m

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