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Re: [DES] Criteria for Key Recovery target.
- To: [email protected]
- Subject: Re: [DES] Criteria for Key Recovery target.
- From: [email protected]
- Date: Tue, 22 Oct 96 18:37:12 EDT
- In-Reply-To: <+cmu.andrew.internet.computing.coderpunks+YmPCtHi00UfAI10Mcw@andrew.cmu.edu>
- Organization: Dr. Beddoes' Pneumatic Institute
- Sender: [email protected]
Russell Holt writes:
>BTW, does anyone have references to statistical comparisons of key
>searches in "real world" settings? Eg, random starting locations
>versus random keys .. etc..
E(time) with all trial keys distinct:
1/N Sigma^N i = N/2 = 2^55.
E(time) for random trials:
1/N + (N-1)/N (1 + E(time))
so E(time) = N = 2^56.
Centralized keyspace handling is a clear lose, IMO. The RC4-40
project had server problems; scaling up by another 2^16 would be
non-trivial. Then there are problems with malicious searchers,
corrupt servers, flaky networks... all this for a factor of two?
(And, admittedly, the reduction in variance.)
To rain on the parade a bit, what this discussion says to me is that
most applications of DES are safe from net cracking for a few years
yet...
--
Eli Brandt
[email protected]