[IP] Swiss on a Roll With Quantum Crypto
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Dave Farber +1 412 726 9889
...... Forwarded Message .......
From: Johan Ovlinger <johan@xxxxxxxxxxx>
To: dave@xxxxxxxxxx
Cc: Ip <ip@xxxxxxxxxxxxxx>
Date: Thu, 30 Sep 2004 17:17:28 -0400
Subj: Re: [IP] Swiss on a Roll With Quantum Crypto
David Farber wrote:
> I suggest that a more accurate statement would be, "It is the only
> solution offering long term confidentiality and which cannot be
> compromised by *CURRENTLY KNOWN* scientific or technological
> advances".
>
> I, for one, don't know where, or when, the next Einstein, or
> Feynman, or Hawking will arrive on the scene. I certainly don't
> know what they will tease out of nature's secret treasure trove.
Dave, Bob, IPers,
as I understand these things (interested layman, at most), quantum
cryptography doesn't actually encrypt anything. Rather, it allows you
to detect whether a message has been intercepted (copied) en-route.
From this, it is fairly easy to build a secure encryption system that
functions over conventional channels. (Don't send the message over the
safe channel, but rather send a one-time-pad, and only use pads not
intercepted.)
The main strength of QC is that while it may possibly be invalidated
by future breakthroughs, these breakthroughs would still not allow the
attacker access to old communications, as without these breakthroughs,
no copies of the old messages could have been made.
Ultimately, this may be a moot breakthrough: as Bruce Schneier points
out, it is rarely -- if ever -- that the cryptosystem is the weak
point in a security breach. Humans and processes are much easier to
break than the crypto itself. People spend millions on security
devices and then leave the password on a post-it note, or don't notice
the key-logger secretly attached to their keyboard's usb cable.
Lastly, although the article doesn't go into specifics, unless they
are happy with transmission rates of ~ 100kbs (I seem to recall a
recent speed record in quantum bit generation around that figure),
they'll need to just use QC for key exchange and resort to
conventional encryption for the bulk of the message itself. In this
case, future breakthroughs in cryptography could very well compromise
old transmitted messages, by merely attacking the conventional crypto-
system.
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