Re: Breaking Triple-DES

Alan Mackenzie writes:

> Is there any way known of breaking single DES, other than by a brute
> force search of all keys?

None that significantly reduce the key space, as far as I know.

The main weakness of DES is simply the inadequate length of the key;
it is now practical to exhaustively search the entire keyspace, making
other methods unnecessary.  I'm surprised that the NSA was so
short-sighted in the design: it failed to accurately predict the rapid
increase in processing power that was to come in computers, and it
failed to predict the true length of time over which DES would be
widely used (a period that extended well beyond the development of
practical brute-force compromises).

Triple-DES is presumably still safe, since DES is not a group (that
is, encrypting three times with three different keys in DES is not
equivalent to any single encryption with any key).

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