r11521@catbus: nickm | 2007-01-26 01:07:55 -0500

 Split tor-spec-v2 and dir-voting into component proposals.


svn:r9417

1 files changed, 0 insertions, 123 deletions

diff --git a/proposals/101-dir-voting.txt b/proposals/101-dir-voting.txt
index 4909701..1a7e776 100644
--- a/proposals/101-dir-voting.txt
+++ b/proposals/101-dir-voting.txt
@@ -253,112 +253,8 @@ by the authorities. -RD]
   post to every other.  The "download if no copy has been received" mechanism
   exists only as a fallback.
 
-3.2. Dropping "opt".
-
-  The "opt" keyword in Tor's directory formats was originally intended to
-  mean, "it is okay to ignore this entry if you don't understand it"; the
-  default behavior has been "discard a routerdesc if it contains entries you
-  don't recognize."
-
-  But so far, every new flag we have added has been marked 'opt'.  It would
-  probably make sense to change the default behavior to "ignore unrecognized
-  fields", and add the statement that clients SHOULD ignore fields they don't
-  recognize.  As a meta-principle, we should say that clients and servers
-  MUST NOT have to understand new fields in order to use directory documents
-  correctly.
-
-  Of course, this will make it impossible to say, "The format has changed a
-  lot; discard this quietly if you don't understand it." We could do that by
-  adding a version field.
-
-3.3. Multilevel keys.
-
-  Replacing a directory authority's identity key in the event of a compromise
-  would be tremendously annoying.  We'd need to tell every client to switch
-  their configuration, or update to a new version with an uploaded list.  So
-  long as some weren't upgraded, they'd be at risk from whoever had
-  compromised the key.
-
-  With this in mind, it's a shame that our current protocol forces us to
-  store identity keys unencrypted in RAM.  We need some kind of signing key
-  stored unencrypted, since we need to generate new descriptors/directories
-  and rotate link and onion keys regularly.  (And since, of course, we can't
-  ask server operators to be on-hand to enter a passphrase every time we
-  want to rotate keys or sign a descriptor.)
-
-  The obvious solution seems to be to have a signing-only key that lives
-  indefinitely (months or longer) and signs descriptors and link keys, and a
-  separate identity key that's used to sign the signing key.  Tor servers
-  could run in one of several modes:
-    1. Identity key stored encrypted.  You need to pick a passphrase when
-       you enable this mode, and re-enter this passphrase every time you
-       rotate the signing key.
-    1'. Identity key stored separate.  You save your identity key to a
-       floppy, and use the floppy when you need to rotate the signing key.
-    2. All keys stored unencrypted.  In this case, we might not want to even
-       *have* a separate signing key.  (We'll need to support no-separate-
-       signing-key mode anyway to keep old servers working.)
-    3. All keys stored encrypted. You need to enter a passphrase to start
-       Tor.
-  (Of course, we might not want to implement all of these.)
-
-  Case 1 is probably most usable and secure, if we assume that people don't
-  forget their passphrases or lose their floppies.  We could mitigate this a
-  bit by encouraging people to PGP-encrypt their passphrases to themselves,
-  or keep a cleartext copy of their secret key secret-split into a few
-  pieces, or something like that.
-
-  Migration presents another difficulty, especially with the authorities.  If
-  we use the current set of identity keys as the new identity keys, we're in
-  the position of having sensitive keys that have been stored on
-  media-of-dubious-encryption up to now.  Also, we need to keep old clients
-  (who will expect descriptors to be signed by the identity keys they know
-  and love, and who will not understand signing keys) happy.
-
-  I'd enumerate designs here, but I'm hoping that somebody will come up with
-  a better one, so I'll try not to prejudice them with more ideas yet.
-
-  Oh, and of course, we'll want to make sure that the keys are
-  cross-certified. :)
-
-  Ideas? -NM
-
-3.4. Long and short descriptors
-
-  Some of the costliest fields in the current directory protocol are ones
-  that no client actually uses.  In particular, the "read-history" and
-  "write-history" fields are used only by the authorities for monitoring the
-  status of the network.  If we took them out, the size of a compressed list
-  of all the routers would fall by about 60%.  (No other disposable field
-  would save more than 2%.)
-
-  One possible solution here is that routers should generate and upload a
-  short-form and long-form descriptor.  Only the short-form descriptor should
-  ever be used by anybody for routing.  The long-form descriptor should be
-  used only for analytics and other tools.  (If we allowed people to route with
-  long descriptors, we'd have to ensure that they stayed in sync with the
-  short ones somehow.)  We can ensure that the short descriptors are used by
-  only recommending those in the network statuses.
-
-  Another possible solution would be to drop these fields from descriptors,
-  and have them uploaded as a part of a separate "bandwidth report" to the
-  authorities.  This could help prevent the mistake of using long descriptors
-  in the place of short ones.
-
-  Thoughts? -NM
-
-3.5. Compression
-
-  Gzip would be easier to work with than zlib; bzip2 would result in smaller
-  data lengths.  [Concretely, we're looking at about 10-15% space savings at
-  the expense of 3-5x longer compression time for using bzip2.]  Doing
-  on-the-fly gzip requires zlib 1.2 or later; doing bzip2 requires bzlib.
-  Pre-compressing status documents in multiple formats would force us to use
-  more memory to hold them.
-
 4. Migration
 
-  For directory voting:
      * It would be cool if caches could get ready to download consensus
        status docs, verify enough signatures, and serve them now.  That way
        once stuff works all we need to do is upgrade the authorities.  Caches
@@ -367,22 +263,3 @@ by the authorities. -RD]
        off very quickly from downloading consensus docs until they're
        actually implemented.
 
-  For dropping the "opt" requirement:
-     * stopped requiring it as of 0.1.2.5-alpha.  Stop generating it once
-       earlier formats are obsolete.
-
-  For multilevel keys:
-     * no idea
-
-  For long/short descriptors:
-     * In 0.1.2.x:
-       * Authorities should accept both, now, and silently drop short
-         descriptors.
-       * Routers should upload both once authorities accept them.
-       * There should be a "long descriptor" url and the current "normal" URL.
-         Authorities should serve long descriptors from both URLs.
-     * Once tools that want long descriptors support fetching them from the
-       "long descriptor" URL:
-       * Have authorities remember short descriptors, and serve them from the
-         'normal' URL.
-