Le 06/05/2011 15:16, Invisible a écrit :
>> DES was used as an illustration. Moreover, the 3*56 bits of 3DES have a
>> lower entropy (so, 3*56 bits is *not* 168, at least in cryptography) due
>> to issue in the model.
> 
> How do you work that one out?

IIRC, it's part of the discussion in the SSH RFCs about the number of
secure bits.
Or it was in a SSH book. 3DES should actually be considered insecure, if
it was not for the administrations of USA to have it deployed a lot.

The wiki about 3DES in french states that 3*56 is 112 due to m-i-t-m
attack. The english version states the same, with added comment about
NIST reducing the actual value to something around 80.

-- 
Software is like dirt - it costs time and money to change it and move it
around.

Just because you can't see it, it doesn't weigh anything,
and you can't drill a hole in it and stick a rivet into it doesn't mean
it's free.

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