[tahoe-dev] several newbie questions

Miles Fidelman mfidelman at meetinghouse.net
Mon Apr 25 14:17:08 UTC 2011


David-Sarah Hopwood wrote:
> On 21/04/11 13:58, Miles Fidelman wrote:
> 1. Tahoe seems to support multi-writer mutable files - but I can't seem to
> find any discussion of consistency management and conflict resolution
> mechanisms.  Are there any, and if so, can someone point me at some
> documentation?
>    
> Brief, but to the point:
> <http://tahoe-lafs.org/source/tahoe-lafs/trunk/docs/write_coordination.html>
>
> Note that updates from multiple clients using the same gateway should be
> consistent. It's only when clients update the same directory using different
> gateways, that data loss may occur.
>    

thanks for the pointer

sounds very dangerous for anything approaching production use

>> The standard problem with key-based capabilities mechanisms is that they
>> can be copied.
>>      
> That's sometimes perceived to be a problem, but there's little evidence from
> real-world capability systems that it actually is a problem.
>
> In practice, security models that try to impose a restriction on delegation
> end up with worse security as a result. For example in an ACL system, the
> owner of an object is forced to anticipate which subjects might need to have
> access. This leads in practice to permissions that are overestimates of the
> needed authority (if they were underestimates, users would not be able to get
> their work done). In a capability system, on the other hand, the same
> identifiers that are used to designate objects also grant access to those
> objects, regardless of the holder's identity. This reduces the administrative
> overhead of managing permissions considerably, and makes it more likely that
> the correct permissions will be granted.
>    

umm... seems to me that anytime something as simple as a URL (even a 
complicated one) is all that's needed to access/change information - any 
notion of privacy or security goes out the window -- too easy to compromise




-- 
In theory, there is no difference between theory and practice.
In<fnord>  practice, there is.   .... Yogi Berra





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