Proposal: Provide diffs between consensuses

Nick Mathewson nickm at
Sat Jun 28 04:26:29 UTC 2008

On Wed, Jun 25, 2008 at 08:30:09AM +0200, Peter Palfrader wrote:
> >   1. There needs to be a spec for generating and applying patches.
> >      The spec for generating them needs to be deterministic (or have a
> >      deterministic variant) so that authorities can all generate the
> >      same patch.
> Why?  Nobody needs to sign patches.  Even directory caches can create
> the patches if we want.  If all works out the end result will be a
> properly signed consensus.

Ah, you're right.  I had assumed a signed-patch thing rather than a
patch-from-signed-to-signed thing.  I take back the "deterministic"
part, but still mean the "specified" part. :)

> >   2. There should be a good Free Software library (3BSD-like license,
> >      ideally) to generate and apply patches.
> Not that I have found one yet, but I didn't look too closely.

There are libraries for diff-related things in at least Python and
Perl, but I haven't yet turned up a C library with a license Tor can
use.  I suppose we could extract the relevant parts of a 3BSD-licensed
"patch" implementation, but that way lies maintenance hell.


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