Richard Brooks writes: > On 6/14/20 2:48 PM, David Stodolsky wrote: > > > > Not true. Strong crypto can’t be cracked. > > Depends on the computational bandwidth. You do not know > how many CPUs/GPUs they have.
That's probably not ultimately the most important question. For example, with AES-256 there is a thermodynamic argument that you can't get the energy you would need to complete a brute-force attack. Schneier famously said about this These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space. This doesn't mean that nobody could ever crack AES-256, but it means that a mathematical insight would be necessary to get a dramatic speedup relative to brute force. The value of that insight would significantly dominate the computational resources in determining the feasibility of the attack. (People have done lots of these calculations with different assumptions. For example, you could use Landauer's principle https://en.wikipedia.org/wiki/Landauer%27s_principle for the pure ideal thermodynamic calculation, or look at current Bitcoin mining hardware -- which represents a huge multi-year, multi-million dollar international commercial effort to optimize the efficiency of brute-force cryptographic search hardware -- and assume that a government can build hardware that is 1,000,000 times more energy-efficient, or something. The fun thing then is that the costs for either hardware or electricity for pure brute-force attacks even on a 128-bit key space will still be comparable to all the resources available in the world. Scalable quantum computers do change these calculations, but as Scott Aaronson tires himself out pointing out, they let you take the square root of the key space, not reduce it to zero.) -- Seth Schoen <[email protected]> Senior Staff Technologist https://www.eff.org/ Electronic Frontier Foundation https://www.eff.org/join 815 Eddy Street, San Francisco, CA 94109 +1 415 436 9333 x107 -- Liberationtech is public & archives are searchable from any major commercial search engine. Violations of list guidelines will get you moderated: https://lists.ghserv.net/mailman/listinfo/lt. Unsubscribe, change to digest mode, or change password by emailing [email protected].
