NODE 8e9b98a9Re: DES
an41418@anon.penet.fi (wonderer)Thu, 14 Oct 93 10:51:59 PDT
I don't think it takes the cube of it. There are 56 bits in
one key, and 112 bits in two keys, so there could not be
an entropy of more than 112 bits to triple DES. It is no
more cryptographically secure than double DES because it
uses 2 keys.
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NODE 7d2b4656Re: DES
"Perry E. Metzger" <pmetzger@lehman.com>Thu, 14 Oct 93 11:11:58 PDT
wonderer says:
> I don't think it takes the cube of it. There are 56 bits in
> one key, and 112 bits in two keys, so there could not be
> an entropy of more than 112 bits to triple DES. It is no
> more cryptographically secure than double DES because it
> uses 2 keys.
In spite of the "standard" most people do triple DES with three keys.
With the two key system, it would take T^2+T time to do the
calculation, where T is the time to crack single DES on your machine.
Perry
NODE 48144fe6Re: DES
Matthew J Ghio <mg5n+@andrew.cmu.edu>Thu, 14 Oct 93 17:32:04 PDT
Wonderer wrote:
> I don't think it takes the cube of it. There are 56 bits in
> one key, and 112 bits in two keys, so there could not be
> an entropy of more than 112 bits to triple DES. It is no
> more cryptographically secure than double DES because it
> uses 2 keys.
Wouldn't "triple-DES" imply three keys, or did I miss something?