This list of open Tor proposals is based on one I sent out in May of
last year. Since I'd like to do this more regularly, I have added to
each description the date when I wrote it. Most of the summaries from
older proposals are unchanged since last May; the later ones in the
list for 6/2012 I wrote pretty quickly since I want to get out the
door tonight for an appointment, but I want to send this list out
without further delay.
OPEN, DRAFT, AND ACCEPTED PROPOSALS:
117 IPv6 exits
IPv6 is still the future, but now it's the kind of future
that's unevenly distributed. It's time to do this one so that
IPv6 traffic can be sent over Tor.
It needs updating to work properly with microdescriptors; it
also has some open questions about DNS. (6/2012)
127 Relaying dirport requests to Tor download site / website
The idea here was to make it easier to fetch and learn about
Tor by making it easy for relays to automatically act as
proxies to the Tor website. It needs more discussion, and
there are some significant details to work out. It's not at
all clear whether this is actually a good idea or not.
(5/2011)
131 Help users to verify they are using Tor
Here's a proposal for making a torcheck-like website more reliable.
If anybody wants to pick it up (especially somebody working on
torcheck) and see whether it should be reopened or rejected, that
would be a fine thing. (5/2011)
132 A Tor Web Service For Verifying Correct Browser Configuration
This proposal was meant to give users a way to see if their
browser and privoxy (yes, it was a while ago) are correctly
configured by running a local webserver on 127.0.0.1. I'm not
sure the status here. (5/2011)
133 Incorporate Unreachable ORs into the Tor Network
This proposal had an idea for letting ORs that can only make
outgoing connections still relay data usefully in the network.
It's something we should keep in mind, and it's a pretty neat
idea, but it radically changes the network topology. Anybody
who wants to analyze new network topologies should definitely
have a look. (5/2011)
140 Provide diffs between consensuses
This proposal describes a way to transmit less directory
traffic by sending only differences between consensuses, rather
than the consensuses themselves. It is mainly languishing for
lack of an appropriately licensed, well-written, very small,
pure-C implementation of the "diff" and "patch" algorithms.
(The good diffs seem to be GPL (which we can't use without
changing Tor's license), or spaghetti code, or not easily
usable as a library, or not written in C, or very large, or
some combination of those.) (5/2011)
141 Download server descriptors on demand
The idea of this proposal was for clients to only download the
consensus, and later ask nodes for their own server descriptors
while building the circuit through them. It would make each
circuit more time-consuming to build, but make bootstrapping
much cheaper.
Microdescriptors obsolete a lot of this proposal, and present
some difficulties in using in a way compatible with
it. (6/2012)
143 Improvements of Distributed Storage for Tor Hidden Service Descriptors
Here's a proposal from Karsten about making the hidden service
DHT more reliable and secure to use. It could use more
discussion and analysis. (5/2011)
144 Increase the diversity of circuits by detecting nodes
belonging the same provider
This is a version of the good idea, "Let's do routing in a way
that tries to keep from routing traffic through the same
provider too much!" There are complex issues here that the
proposal doesn't completely address, but I think it might be a
fine idea for somebody to see how much more we know now than we
did in 2008, particularly in light of the relevant paper(s) by
Matt Edmann and Paul Syverson. (5/2011)
145 Separate "suitable as a guard" from "suitable as a new guard"
Currently, the Guard flag means both "You can use this node as a
guard if you need to pick a new guard" and "If this node is
currently your guard, you can keep using it as a guard." This
proposal tries to separate these two concepts, so that clients can
stop picking a router once it is full of existing clients using it
as a guard, but the clients currently on it won't all drop it.
It's not clear whether this has anonymity issues, and it's not
clear whether the imagined performance gains are actually
worthwhile. (5/2011)
146 Add new flag to reflect long-term stability
From time to time we get the idea of having clients ship with a
reasonably recent consensus (or a list of directory mirrors),
so instead of bootstrapping from one of the authorities, they
can bootstrap from a regular directory cache. The problem here
is that by the time the client is run, most of the directory
mirrors will be down or will have changed their IP. This
proposal tries to address that.
It needs analysis based on behavior of actual routers on the
network to see whether it could work, and what parameters might
work.
Nevertheless, we should really do something like this, so that
we can ship a list of initial directory mirrors with Tor
(possibly via the "fallback consensus" deisgn), so that new
bootstrapping Tor clients don't all hammer the directory
authorities. (6/2012)
147 Eliminate the need for v2 directories in generating v3 directories
This proposal explains a way that we can phase out the
vestigial use of v2 directory documents in keeping authorities
well-informed enough to generating the v3 consensus. It's
still correct; somebody should implement it before the v2
directory code rots any further. (5/2011)
156 Tracking blocked ports on the client side
This proposal provides a way for clients to learn which ports
they are (and aren't) able to connect to, and connect to the
ones that work. It comes with a patch, too. It also lets
routers track ports that _they_ can't connect to.
I'm a little unconvinced that this will help a great deal: most
clients that have some ports blocked will need bridges, not
just restriction to a smaller set of ports. This could be good
behind restrictive firewalls, though.
The router-side part is a little iffy: routers that can't
connect to each other violate one of our network topology
assumptions, and even if we do want to track failed
router->router connections, the routers need to be sure that
they aren't fooled into trying to connect repeatedly to a
series of nonexistent addresses in an attempt to make them
believe that (say) they can't reach port 443.
This one is a paradigmatic "open" proposal: it needs more
discussion. The patch probably also needs to be ported to
0.2.3.x; it touches some code that has changed. (5/2011)
157 Make certificate downloads specific
This proposal added cross-certification and
signing-key-specific download URLs for directory authority
certificates. It is IIRC mostly implemented on the server
side; there are just some SHOULDs that we should turn into
MUSTS if all sufficiently old authority certificates are now
obsolete, and a client-side portion that we need to implement.
(6/2012)
159 Exit Scanning
This is an overview of SoaT, with some ideas for how to integrate
it into Tor. (5/2011)
162 Publish the consensus in multiple flavors
The initial proposal here is done, but more work is needed for
forward-compatibility: we'd like to have caches be willing to
cache and serve consensus flavors which they do not currently
recognize. (6/2012)
164 Reporting the status of server votes
This proposal explains a way for authorities to provide a
slightly more verbose document that relay operators can use to
diagnose reasons that their router was or was not listed in the
consensus. These documents would be like slightly more verbose
versions of the authorities' votes, and would explain *why* the
authority voted as it did. It wouldn't be too hard to
implement, and would be a fine project for somebody who wants
to get to know the directory code. (5/2011)
165 Easy migration for voting authority sets
This is a design for how to change the set of authorities without
having a flag day where the authority operators all reconfigure
their authorities at once. It needs more discussion. One
difficulty here is that we aren't talking much about changing the
set of authorities, but that may be a chicken-and-egg issue, since
changing the set is so onerous.
If anybody is interested, it would be great to move the discussion
ahead here. (5/2011)
168 Reduce default circuit window
This proposal reduces the default window for circuit sendme cells.
I think it's implemented, isn't it? If so, we should make sure
that tor-spec.txt is updated and close it.XXXXXXX (5/2011)
172 GETINFO controller option for circuit information
173 GETINFO Option Expansion
These would help controllers (particularly arm) provide more
useful information about a running Tor process. They're
accepted and some parts of 173 are even implemented: somebody
just needs to implement the rest. (5/2011)
175 Automatically promoting Tor clients to nodes
Here's Steven's proposal for adding a mode between "client
mode" and "relay mode" for "self-test to see if you would be a
good relay, and if so become one." It didn't get enough
attention when it was posted to the list; more people should
review it. (5/2011)
177 Abstaining from votes on individual flags
Here's my proposal for letting authorities have opinions about some
(flag,router) combinations without voting on whether _every_ router
should have that flag. It's simple, and I think it's basically
right. With more discussion and review, somebody could/should
build it for 0.2.4.x, I think. (6/2012)
182 Credit Bucket
This proposal suggests an alternative approach to our current
token-bucket based rate-limiting, that promises better
performance, less buffering insanity, and a possible end to
double-gating issues. (6/2012)
185 Directory caches without DirPort
The old HTTP directory port feature is no longer used by
clients and relays under most circumstances. The proposal
explains how we can get rid of the requirement that non-bridge
directories have an open directory port. (6/2012)
186 Multiple addresses for one OR or bridge
This one is partially implemented, in that bridges can have
IPv6 addresses. Still to go: we need to let ORs have IPv6
addresses too. Undecided: is one IPv4 and one IPv6 enough for
anybody? (6/2012)
188 Bridge Guards and other anti-enumeration defenses
This proposal suggests some ways to make it harder for a relay
on the Tor network to enumerate a list of Tor bridges. Worth
investigating and possibly implementing. (6/2012)
189 AUTHORIZE and AUTHORIZED cells
190 Bridge Client Authorization Based on a Shared Secret
191 Bridge Detection Resistance against MITM-capable Adversaries
Proposal 187 reserved the AUTHORIZE cell type; these proposals
suggests how it could work to try to make it harder to probe
for Tor bridges. They need more alternatives and attention, and
possibly some revision and analysis. (6/2012)
192 Automatically retrieve and store information about bridges
This proposal gives an enhancement to the bridge information
protocol, where clients remember more things about bridges, and
are able to update what they know about them over time. Could
help a lot with bridge churn. (6/2012)
194 Mnemonic .onion URLs
Here's one of several competing "let's make .onion URLs
human-usable" proposals. This one makes sentences using a
fixed map. (6/2012)
195 TLS certificate normalization for Tor 0.2.4.x
Here's the followup to proposal 179, containing all the parts
of proposal 179 that didn't get built, and a couple of other
tricks besides to try to make Tor's default protocol less
detectable. I'm pretty psychoed about the part where we let
relays drop in any any self-signed or CA-issued certificate
that they like. (6/2012)
196 Extended ORPort and TransportControlPort
Here are some remaining pieces of the pluggable transport
protocol that give Tor finer control over the behavior of its
transports. (6/2012)
197 Message-based Inter-Controller IPC Channel
This proposal is for an architectural enhancement in Tor
deployments, where Tor coordinates communications between the
various programs (Vidalia, TorBrowser, etc) that are using
it. (6/2012)
198 Restore semantics of TLS ClientHello
Partially implemented. We have the new client behavior in place
in 0.2.3.x, but not the new server behavior which it
permits. (6/2012)
199 Integration of BridgeFinder and BridgeFinderHelper
Here's a proposal for how Tor can integrate with a client
program that finds bridges for it. (6/2012)
200 Adding new, extensible CREATE, EXTEND, and related cells
We'd like to moved to better authentication and key agreement
mechanisms in future versions of Tor. This proposal gives us an
extensible replacement for our current CREATE/CREATED cell
mechanism. (6/2012)
201 Make bridges report statistics on daily v3 network status requests
Here's a proposal for bridges to better estimate the number of
bridge users. (6/2012)
