Re: Re: Chaum's cash: backup?

"James A. Donald" <jamesd@echeque.com> wrote:
>>if it was like "real" cash, then it really would be lost.
>It is really lost.
>Your disk drive contains information the bank *cannot* know.
>If you do not know that information either, you cannot prove to
>the bank or anyone else that you rightfully possess a legitimate coin.

You seem to have different information than we have. Strange. Please 
reread the press release.

I could give a hint: your random state initializer is not the too-often 
used srand( time( NULL ) ) but user-chosen during installation. Write 
that initializer down and you can re-generate all coins. The bank can 
check wether these coins were indeed signed, and, after revealing 
blinding factors, the bank can also check if they were used. The 
difference must have been on your disk.

This system is not completely operational yet but will be used in the 
future.

// Marcel van der Peijl, DigiCash bv, http://www.digicash.com/~bigmac/
// "If you had to tell the Whole Truth, you'd never shut up."

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Hello Marcel van der Peijl <bigmac@digicash.com>
  and jamesd@echeque.com, cypherpunks@toad.com

MvdP wrote:
> "James A. Donald" <jamesd@echeque.com> wrote:
> >>if it was like "real" cash, then it really would be lost.
> >It is really lost.
...
> I could give a hint: your random state initializer is not the too-often 
> used srand( time( NULL ) ) but user-chosen during installation.

This sounds great... Will the bank be running crack against the proto-coins
it gets? (Say, at the behest of a LEA?)

Is there any way for the user to re-initialize the random state?

> Write that initializer down and you can re-generate all coins.
...

That's going to be one hell of a valuable piece of paper.
(Certainly to your enemies/prosecutors - it reveals the blinding factors
for every coin you ever spent.)


Please tell me I've got it all wrong...

Jiri
- --
If you want an answer, please mail to <jirib@cs.monash.edu.au>.
On sweeney, I may delete without reading!
PGP 463A14D5 (but it's at home so it'll take a day or two)
PGP EF0607F9 (but it's at uni so don't rely on it too much)

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