at Thursday, October 17, 2002 2:20 AM, Sam Ritchie
<[EMAIL PROTECTED]> was seen to say:
> ACTUALLY, quantum computing does more than just halve the
> effective key length. With classical computing, the resources
> required to attack a given key grow exponentially with key length. (a
> 128-bit key has 2^128 possibilities, 129 has 2^129, etc. etc. you all
> know this...) With quantum computing, however, the complexity of
> an attack grows only polynomially.
Is this actually true or is it that it can scale proportionally in time
and in number of qbits required? if you assume that a classic machine
takes x^2 operations to break a key, but a quantum machine will take x
operations with x qbits, that would have the same effect, provided you
can create that many qbits. I haven't seen any papers that say that it
is polynomial at all though - can you provide a reference or two?
