Firewall Wizards mailing list archives

Re: R: strong encryption for Europeans


From: Andreas Siegert <afx () ibm de>
Date: Tue, 25 Nov 1997 08:50:12 +0100


If keys are changed often enough, I think 56 bits is still pretty much ok for
most uses. It depends very much on the lifetime of the data transfered versus
the time needed to crack the key. If the key is changed every 15 minutes (and
I assume a much stronger protection on the key exchange), then the attacker
not only has to deal with finding the key, but also with finding the window in
which the data he is interested in was transferred.

On the other hand, has anyone used the ssh VPNs yet?

cheers
afx

Quoting Franco RUGGIERI (fruggieri () selfin net):
Recently (June and October this year), attacks have been successfully
accomplished against DES and RC5 56 bit, by a huge number of computers
coordinated via Internet. Since participation in such effort was voluntary,
I wouldn't define such coordination as *strict*. Thus, we can assume that a
well determined organization would break codes based on keys up to 56 bit
in a reasonable amount of time. Therefore I wouldn't recommend VPNs based
on such systems (RCx, DES and the likes with *short*keys), unless for what
I would dub *minor areas* and for not long lasting applications.
This, of course, IMHO. I would appreciate comments (not flames!) on this
viewpoint of mine.

-- 
Andreas Siegert       afx () ibm de / afx () barolo munich de ibm com / AFX at IPNET
PGP Key:http://www.muc.de/~afx/pubkey.asc, KeyId AB26FD05



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