Re: quantum computing

<steiffcollector@xxxxxxxxx> wrote in message
news:1143560098.203076.133810@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
An article in New Scientist says that "A practical quantum computer
is now less than 10 years away"

Yeah and Itanium will have 90% of the market by 2005. Basically QCs seem to
be growing at < 1qubit per year (growth is too sporadic to get a good
extrapolation curve), and they're currently at about 10 qubits, so just to
be able to put the entire AES block in memory you're looking at another 100
years at the current rate, even applying something like Moore's law to it
we're looking at a couple decades. As far as a truly practical QC, I think
we're looking at 30 years before the scientific community has access to one,
and 60+ years before humans do.

ANSI X9.62 says that 128-256 bit encryption is good until "Beyond
2030".

Do the ANSI estimates take quantum computing into account?

Yes they do. QCs only accelerate by a square root, so 128-bit is reduced to
2^64 complexity, 256-bit to 2^128.

How do we change our encryption today if we want our messages to remain
secure "Beyond 2030"?

With the dependability of cryptography, basically you don't. If you want to
try, and make a good guess about it you use all the AES finalists in a chain
and repeat the chain 3 times, let's just go ahead and call this algorithm
stack Grind because it will make your system Grind to a halt. I could also
have called it Pray because you'll have to pray that it doesn't get broken.

Or you can take the more reasonable route and re-examine your security
periodically to see if it still meets your needs. Incidentally this would be
the general concensus method because either way you'll have to.
Joe


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