thoughts on RC4

[Perry E. Metzger]

Mike Johnson second login says:
> Don't forget the precomputation attack.  The key setup only has to be done
> 2^40 times, ever.  The initial state of the stream cipher can be stored on
> a set of tapes that are read in parallel to perform the brute force
> attack. 

You may be interested to know that the SPA/NSA agreement covered this;
you are allowed to use a 40 bit "salt" thats appended to the key when
you use RC4 in an exported application provided the salt is sent along
with the message.

.pm