[tahoe-dev] [tahoe-lafs] #956: embed security metadata in parent directory

Kevin Reid kpreid at mac.com
Wed Feb 17 00:26:19 UTC 2010

On Feb 17, 2010, at 8:45, James A. Donald wrote:
> tahoe-lafs wrote:
>> #956: embed security metadata in parent directory
>> There is going to be a compatibility problem with doing this, since
>> we don't (as far as I can see) have anywhere in the directory
>> format to encode new fields that will be ignored by old clients.
>> This will also be a problem with several other proposed features,
>> including deep-verify caps as described in #308, and extensible
>> directories suggested as part of #959.
> The COM approach to addressing this type of problem is that the  
> client should never see the raw data of a structured object, rather  
> a presentation of that data, and the presentation depends on the  
> negotiated interface, so older clients see an older presentation.

The "client" here is the client of the storage servers, which hold  
only encrypted shares and are intended to be ignorant of the contents,  
so it would be difficult for them to adapt the interface. This is a  
data-format-compatibility issue, not protocol compatibility.

The client *of a Tahoe client-node*, client of the Tahoe webapi, can  
be adapted to as you describe.

Kevin Reid                                  <http://switchb.org/kpreid/>

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