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Re: [Auth]My two cents

From: Norbert Sendetzky
Subject: Re: [Auth]My two cents
Date: Tue, 17 Jul 2001 15:22:22 +0200

On Monday 16 July 2001 15:36, you wrote:
> What about two (or more) registrars that store half of the information
> each?!
> For example, take two registrars, and The user wants to
> store his profile, given as an array of bytes p[i], with these registrars
> without
> trusting any of them. This can be done by taking an array of random numbers
> r[i].
> Registrar gets to store the array r[i], and registrar
> gets to store the array r[i] XOR p[i]. Both registrars only see arrays of
> random numbers. In order to recreate the original profile, the client has
> to retrieve
> r[i] from, and  r[i] XOR p[i] from, and XOR these two
> arrays
> with each other resulting in r[i]XOR r[i] XOR p[i] == p[i]. So this reduces
> the
> problem to the problem of reliably updating profile arrays at two
> registrars which can be solved by storing two generations of profile
> arrays.

I can't be sure that a few registrars combine the data to get the 
information. See Doubleclick and Abacus!

With encryption this is very unlikely.


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