Simon J. Gerraty <sjg @
frodo .
dn .
itg .
telecom .
com .
au> wrote:
> What a lot of folk would like is to beable to have secure key exchange
> without the need for trusted 3rd parties (eg certifying authority...).
[stuff deleted]
> However to beat a MMA use DH key exchange and then you really just
> need to verify that client and server have the _same_ key. Shamir &
> Rivest (hope I spelled them right), showed how to do that provided you
> have a shared secret. The method is used by STEL.
The problem, however, is that it is not trivial to distribute that "shared
secret" via an insecure channel. If you call your shared secret something
like a "Private/public key pair", then you have simply removed key management
to a higher level.
Don't get me wrong, D-H is almost certainly the right way to do things,
especially after the patents expire in 18 months. However, the question
becomes "how do I know that your public key is really YOURS, rather than
someone attempting a man-in-the-middle attack?" It is to answer that
question that people are doing things like PGP key signing parties and
3rd party certifiers.
--
- Ted
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Ted Doty, Network Systems Corporation | phone: +1 301 596-2270
8965 Guilford Road, Suite 250 | fax: +1 410 381-3320
Columbia, MD, 21046 USA | voice mail: (800) 233-1485
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