[Cryptography] soft chewy center

[bmanning at vacation.karoshi.com]

On Tue, Sep 10, 2013 at 07:05:40PM -0400, Perry E. Metzger wrote:
> On Tue, 10 Sep 2013 21:58:28 +0000 bmanning at vacation.karoshi.com
> wrote:
> > some years back, i was part of a debate on the relative value of
> > crypto - and it was pointed out that for some sectors,  crypto
> > ensured _failure_ simply because processing the bits introduced
> > latency.  for these sectors, speed was paramount.
> > 
> > think HFT or any sort of "Flash Mob" event where you want in/out as
> > quickly as possible.  
> 
> The latency cost of a stream cipher implemented in hardware can be as
> little as the time it takes a single XOR gate to operate -- which is
> to say, low even by the standards of my friends who do high frequency
> trading (many of whom do, in fact, claim to encrypt most of their
> communications).

	latency effect should, as you state, be a factor in which 
	tool gets used.  for the HFT crowd, i'm fairly confident they
	are talking about channel protection - they have a fairly simple
	and easily scoped topology.  

> Certainly crypto is not the only (or even most important) way to make
> systems secure. In breaking in to a system, implementation bugs are
> where you look, not cracking cipher keys. However, latency qua
> latency seems like a poor reason to avoid encrypting your traffic. It
> might, of course, be a reason to avoid certain architectural
> decisions in how you use the crypto -- a public key operation per
> packet would clearly add unacceptable latency in many
> applications.

	agreed.

> 
> 
> Perry
> -- 
> Perry E. Metzger		perry at piermont.com