CDR: Re: Schneier: Why Digital Signatures are not Signatures (was

[David Honig]

Herr Bear's two paragraphs below are among of the most clear, concrete
explanations of 'why security is hard/ crypto is insufficient' that I've
read.   Clear to a programmer, anyway.

But still, I think that the vast majority of users will end up
trusting something, and the vast majority will be well secured.
Most do not, for example, worry about black-bag jobs.

How many hardcore cpunks have reverse engineered the source
to the security apps they actually use?  PGPDisk *and* PGPfone *and*
PGP version whatever?  With time left over for SSL? And you do regular RF
sweeps too?   Do you work on your own brakes, too?  

Maybe some need to, and they recognize this.  Most don't, and recognize
this.  The ones who need it but don't see it get culled.  The ones who
don't need it
but see it are paranoid, or cautious, depending.

Finally, things will get deployed (and paid for) only when there's some
utility to the deployees.  Either AMEX is going to pay for all these
cards & readers because its worth it to AMEX, or Homer & vendors are going
to pay because its worth it to them.  

With the current $50 credit card fraud limit
on the customers' side, and the generally reliable POTS dial up to the
credit card folks on the vendors', there is little motivation to change...
no matter how efficient (cheap) or convenient the future might be if we
were to start now.  


[I am reminded of the following: California mandates (suppressing the
"needs killing" remarks for now) electric car sales, but drivers won't buy
them. Rational drivers will buy (initially) more expensive but efficient
hybrids if and only if (when) the price of petrol goes up enough to make it
worthwhile.  Ergo, If people were responsible for much more fraud-debt,
they might accept / pay for / require more secure tech.  Economics is physics.

These are testable hypotheses; look to expensive-petrol places (Euro) to 
buy into high-milage hybrids faster, and 12-cylinder Caddys to be
cruising the oil-rich nations until they're dry]

You can get people to carry metal things around *all the time*, and you can
sell them things to stick the metal things into, if they see a benefit
---like someone not stealing their padlocked objects.  $50 of fraud,
inertia/protectionism, and a general lack of use/concern for anonymity
means Hettinga's Stored Value Smartcard-Requiring Utopia (tm) is a few
years off.


.....

I wonder if Gutenberg had to put up with:
"But why print so many books?  Almost everyone can't read"

......


At 01:49 PM 11/16/00 -0500, Ray Dillinger wrote:
>Which mostly consists of pointing out flaws and problems with 
>things other than the encryption/decryption algorithms in use: 
>Bits of it are definitely worth a read between auditing routines 
>in your code.  (oh yeah, I have 64 bits of key in this local 
>variable, and I'm exiting the routine: better remember to write 
>over them so whatever grabs the memory next can't read them....
>and while I'm at it, I better declare that 'volatile' so the 
>system can't swap it to disk...) 
>
>This stuff is why you can't just plug libraries together and 
>have a good crypto product; A 'math library' made for crypto 
>has to do fundamental things to prevent other applications 
>getting their hands on 'numbers' that a math library for general 
>application does not have to do.  Ditto a windowing or GUI system 
>made for crypto, etc.  All these slap-together GUI programs 
>made with MFC etc that we're seeing, are a completely wrong 
>approach for cryptographic software; you can't make that stuff 
>secure, you have to write your own.  And this is what Schneier 
>has been pointing out. And thank goodness somebody's been 
>pointing it out. 
>