Russell Nelson <[EMAIL PROTECTED]> wrote:
>> Okay, then can I ask a silly question (I prefer to contribute good
>> answers, but in this case hopefully the question is good enough)? If
>> quantum computers make brute-force cryptanalysis tasks easier, don't
>> they also make brute-force cryptographic tasks easier as well? Put
>> another way, is there something special about quantum computers that
>> is different from Intel's next process shrink? That is, apart from
>> the havoc it plays with key lifetime expectations?
bram <[EMAIL PROTECTED]> responded:
>I very strongly suspect that if the encrypter and decrypter are given the
>same oracle, then the encrypter can always force the decrypter to have to
>use vastly more operation of the oracle to do break a cipher than are
>required to encrypt it, even with essentially normal key lengths.
The problem to worry about, of course, is that maybe not everyone is
going to have access to the same oracle.
There is no guarrantee that quantum computing will be as accessible
or as widely used as today's digital computers are. The scale and type of
technology required to isolate, manage, and manipulate the qubit (the
quantum analogue to the digital bit) seems a little daunting, but it is
probably still too early to make any big generalizations like this.
(Any intrusion of an electromagnetic field, even light, can reduce
the multi-state quantum circus to a merely digital platform.)
Consider what was involved when the NIST lab at Boulder created a
qubit a couple of years ago. As I recall, to get their qubit they had to
trap a single atom with missing electrons (an ion) and two energy levels by
nailing it down with an array magnetic and electric fields at minus 273
degrees C.
I figure that I'm not likely to have the wherewithall to manage that
on my desktop anytime soon -- but then, I don't know much about the
alternative designs for ion traps either.
Just using the reports on qubit management out of NIST, Los Alamos,
and the California Institute of Technology for scale, however, you can see
why the cognoscenti had such a belly laugh over the report in the Sunday
Times (UK) a couple weeks ago that the Weizmann Institute in Israel had
developed a hand-held quantum computing device for cryptanalysis.
Suerte,
_Vin
--------
"Cryptography is like literacy in the Dark Ages. Infinitely potent, for
good and
ill... yet basically an intellectual construct, an idea, which by its nature
will
resist efforts to restrict it to bureaucrats and others who deem only themselves
worthy of such Privilege." _A Thinking Man's Creed for Crypto _vbm
* Vin McLellan + The Privacy Guild + <[EMAIL PROTECTED]> *
