> Date: Mon, 21 Aug 2000 22:15:15 -0500
> Subject: Re: [Freenet-dev] A clear point by point comparison of the metadata 
> formats
> From: "Scott G. Miller" <scgmille at indiana.edu>
>
> > Why is this an issue?
> > Why even separate private data into metadata and data?
> Because it allows for complicated metadata to be retrieved separately from
> the data for speed.  For example, you can 'stat' a freenet file by issuing
> a request for the metadata only section of a document.  The node returns
> only "Metadata-length" bytes of the document.

So the question is (using the example of a redirect message):
On a metadata "stat" request, do we want the client to redirect the
metadata request to the actual redirect-referenced location or just
get the metadata from the redirect?

If we want the client to redirect the stat then the redirector belongs
in the stat-reply (aka metadata section, tigglytops section (or
something like that), etc.). If we don't want it to redirect the stat
then the redirector belongs in the non-returned "data" section of
the message.

On a stat, we are guaranteed to get back metadata. Whether or not
it is in the agreed-upon FNP style all depends on how well
behaved the inserting clients were when sticking things in there
in the first place. There is nothing stopping other "unofficial"
clients from setting metadata-length==data-length but not using
FNP (with good or bad intentions).

Good programming practice would be able to handle this properly.
This entails some validity checking of the returned metadata to see
what format it is in rather than parsing it *assuming* it was FNP
because those two values were the same.

On another note ... what validity checks for the stat-reply is there?
Can an intermediate node swap the contents of the encrypted
stat-reply or is a signature being generated on just the metadata
portion too? I know that this stuff will still be encrypted but it
should have the same protections as the rest of the data. An evil
node swapping redirects with knowledge of the encryption key
could cause some havok (not to mention redirect requests to
keys it knows its node is close too)

Mike


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