Re: Is two times encrypting ALWAYS more secure than one time encrypting ???

From: phn@icke-reklam.ipsec.nu
Date: 05/09/02


From: phn@icke-reklam.ipsec.nu
Date: 9 May 2002 19:35:19 GMT

Barry Margolin <barmar@genuity.net> wrote:
> In article <abeblu$irc$2@nyheter.crt.se>, <phn@icke-reklam.ipsec.nu> wrote:
>>In comp.security.misc Sven Fischer <sven_20@mail.com> wrote:
>>> A question concerning the security of encrypting. Assume we have two different
>>> encryption tools.
>>
>>> Does it improve the security (uncrackability) of the starting text if I encrypt
>>> this text with one tool and than afterwards with another ?
>>
>>No, not really.
>>
>>If one is using secure encryption, one run is enough.

> What about things like Triple-DES -- isn't that essentially running the
> text through DES encryption three times? If multiple encryptions doesn't
> buy you anything, why do this?

It does so while extending key length to 112 bits. The point is
the longer key, not that DES is used several times.

> P.S. Wouldn't this discussion really be more appropriate for sci.crypt?

> --
> Barry Margolin, barmar@genuity.net
> Genuity, Woburn, MA
> *** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
> Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

-- 
Peter Håkanson         
        IPSec  Sverige      ( At Gothenburg Riverside )
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