Re: NSA Turns To Commercial Software For Encryption
At 10:01 PM 10/26/03 -0600, J.A. Terranson wrote:
On Sun, 26 Oct 2003, Eugen Leitl wrote:
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In the case of the NSA deal, the agency wanted to use a 512-bit key for the ECC system. This is the equivalent of an RSA key of 15,360 bits."
Am I the only one here who finds this "requirement" excessive? My god: are we looking to keep these secrets for 50 years, or 50000 (or more) years?
In meatspace engineering of life-critical systems, you might design for a few times more than you need under worst-case conditions. Eg, on a bridge: high winds, heavy trucks densely spaced, poor maintenance, poor materials. Remember that bridges fall down when you do something new, like use steel. Or nowadays: planes fall out of the sky because you don't know how composites fail. The NSA might be hedging against future algorithmic improvements. If tomorrow you could factor numbers (or the ECC equivalent) with twice the number of bits, will your spies die? Cf. East German Stasi files, and some south-american files being cracked.
Sorry if this discussion At 08:50 AM 10/27/2003 -0800, Major Variola (ret) wrote:
At 10:01 PM 10/26/03 -0600, J.A. Terranson wrote:
On Sun, 26 Oct 2003, Eugen Leitl wrote:
In the case of the NSA deal, the agency wanted to use a 512-bit key for the ECC system. This is the equivalent of an RSA key of 15,360 bits." Am I the only one here who finds this "requirement" excessive? My god: are we looking to keep these secrets for 50 years, or 50000 (or more) years? .. The NSA might be hedging against future algorithmic improvements. If tomorrow you could factor numbers (or the ECC equivalent) with twice the number of bits, will your spies die? Cf. East German Stasi files, and some south-american files being cracked.
"Excessive" implies a cost-benefit analysis - does anybody know how slow 512-bit ECC calculations are in practice? If they're similar in speed to 512-bit RSA, it's usually fine; if they're similar in speed to 15360-bit RSA, that's maybe a bit slow, but if encryption and decryption are only a bit slower than 2048-bit RSA, it doesn't usually matter if key generation is slower. Also, while there are _lots_ of applications where short keys rock, like James Donald's Crypto Kong signature lines, or dumb smartcards, 512-bit isn't too bad, and there are applications where it's usable and 4096-bit RSA keys take up too much space (e.g. including any signed data in a 576-byte TCP/IP packet.) But more importantly, the algorithms are only starting to be explored. We've got a few hundred years of understanding about primes and factoring, and even then the applications of computer technology to factoring have gotten a big Moore's Law hit since R,S,A,D,H, PRZ, and the Cypherpunks started messing with them; 384-bit RSA keys have gone the way of Bass-O-Matic. ECC is a much newer set of theory, especially for the kinds of attacks cryptographers care about, and it's exposed to risks from algorithm theory and number-crunching practice.
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Bill Stewart -
Major Variola (ret)