[cryptography] The Government and Trusted Third Party

Ian G iang at iang.org
Sun Sep 18 06:31:17 EDT 2011


On 18/09/11 7:55 PM, M.R. wrote:
> On 18/09/11 09:12, Jeffrey Walton wrote:
>>
>> If you can secure the system from the government...
>  >
> I can't possibly be the only one here that takes the
> following to be axiomatic:
>
> +++
> A communication security system, which depends on a corporate
> entity playing a role of a ~trusted-third-party~, can not be
> made secure against a government in whose jurisdiction that
> trusted-third-party operates.
> +++


Right.

> On the other hand, a perfectly adequate low-level retail
> transaction security system can best be achieved by using a
> trusted-third-party, SSL-like system.


That's a marketing claim.  Best ignored in any scientific discussion.

> It follows then that we are not looking at replacing the SSL
> system with something better, but at keeping the current
> SSL - perhaps with some incremental improvements - for the
> retail transactions,


Actually, I'd say the above conclusion follows from normal inertia 
considerations.  We can't wholesale replace SSL because there are too 
many links and lumps and levels and locales involved.

So the question is, how to tweak the current application to deal with 
the mismatch between design and use?


> and designing a new system, from the
> ground up, based on some a-priory, contemporary and well
> documented threat model. This new system should address
> those applications which have spilled outside of the
> (implied?) threat model on which the SSL design was based.
> That new threat model must not fail to explicitly state just
> who are the attackers are and what their capabilities and
> motivations must be considered.


This would be a classical text book approach, but is unrealistic.

In the real world, figure out who is going to do this.  The "who" will 
dramatically drive the process.  Including the list of attackers, their 
capabilities, etc.  E.g., if Google does it, we get one result;  if 
China University School of CS do it, another result.

iang



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