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[liberationtech] Fw: Concept for takedown-resistant publishing

Daniel Margo dmargo at eecs.harvard.edu
Thu Feb 2 17:02:37 PST 2012


Let me try to explain what is and isn't technically difficult about this 
idea. Feel free to pass it around. I have cc'd the liberationtech list.

Torrent is an open protocol. There are numerous open source torrent 
libraries. Opera can download torrents natively, for Firefox there are 
extensions to do this, and so far as I know every browser has some kind 
of plug-able framework for MIME type (Internet media type) handling. To 
have a browser download and then open a torrent of a page is totally 
realistic, and probably not that much code.

The problem is that this is not the actual technical challenge. The 
actual challenges are these:
1. Name resolution: How do I find the torrent file, and then the P2P 
cloud itself?
2. Updates: How do I share a Web site as a living, updating document?
3. Server backend: Is it realistic to run a modern Web site without a 
client-server relationship?

1. Name resolution comes in two parts: finding the torrent file, and 
then finding the actual P2P cloud. Web sites like The Pirate Bay 
function as name resolution services for finding torrent files, but 
obviously any single such server can be blocked. What I presume we 
actually desire is a name resolution service just like DNS for Web 
sites: you type in a URL, it gets resolved to a torrent file.

URLs have a hostname and a path, e.g. 
"www.hostname.com/path/to/torrent.file". "www.hostname.com" is resolved 
by DNS to a server, and then "/path/to/torrent.file" is resolved by that 
server. So unfortunately, you don't gain any takedown resistance by 
hosting your torrent file at "www.myserver.com/my.torrent", because if 
"www.myserver.com" is taken down, then "/my.torrent" can't be resolved. 
So what you would actually need is for DNS to provide hostname 
resolution directly into torrents. This is a sweet idea, but changing 
DNS is hard.

Even if you could do that, well, what's in a "torrent file"? A torrent 
file contains information to get you joined into the P2P cloud; 
specifically, it contains the address of a tracker, a central server 
that gates entry into the cloud. If the tracker is down or blocked by 
some technology, you can't enter the cloud. This is primarily a weakness 
of the BitTorrent protocol, and not the idea itself; there are 
extensions to BitTorrent and other P2P protocols that are resilient to 
this weakness. But fundamentally, finding your way into the P2P cloud is 
an act of name resolution to find other peers in the cloud, which is 
most easily done by a name resolution server, in this case the tracker. 
If we're going about making changes to DNS, probably the most 
technically sane (but politically unrealistic) solution would be for DNS 
itself to provide tracking capability for the cloud. Again, that is a 
sweet idea, but changing DNS is hard.

I don't mean to suggest these issues are insurmountable, merely that 
this is the actual Hard Part.

2.  In order to support dynamic content there has to be a cryptographic 
distinction between updates coming from the legitimate publisher of the 
site (Alice), and subterfuge coming from Evil Eve. Cryptographic 
authentication might be authenticated by the data being shared (e.g. 
this data is signed by Alice, and everybody knows her signature) or by 
the P2P network itself (e.g. in addition to sharing the torrent, the 
servers also provide a distributed authentication service that will only 
accept updates signed by Alice). I am by no means an expert on this 
subject, so I will refrain from talking about it extensively, but I 
bring it up merely because cryptography is non-optional for any dynamic 
scheme, and I'm not aware of any update-able, cryptographically-secured 
P2P torrents. It sounds like maybe they should exist? It also sounds 
Hard, and Google isn't turning anything up.

Again, I'm not suggesting these issues are insurmountable; in some sense 
Google Docs does all this. But they do it with a pretty sophisticated 
backend that glues many technologies together (I guarantee Google has a 
killer internal name resolution and authentication service), and I have 
no idea how Hard it would be to make those parts takedown-resistant (in 
the sense that there are no central servers. There are unquestionably 
central servers at Google).

3. The real elephant in the room is that modern Web sites are best 
thought of as programs, not files, and program distribution is 
infinitely harder than file distribution. When you visit a Wordpress 
blog, what you appear to receive is an HTML file: but in actuality that 
HTML was streamed by a PHP script running on the server talking to a 
MySQL database. The number of layers in this onion is arbitrary; it's 
anything you could run on a computer. Arbitrary code, or I could hook 
MSPaint up to the thing if I wanted it enough. Distributing *and 
executing* arbitrary code like this is Quite Possibly Impossible, and if 
it is possible it is Very Far Away. At any rate, BitTorrent can't do this.

The word "arbitrary" is important. In specific cases, you can certainly 
find a case-specific resolution. Diaspora is building something like a 
distributed social network "program", and I do honestly believe that 
with a lot of code and hard thinking, you could distribute a Wordpress 
blog's backend on P2P. It would probably require a total rewrite of 
Wordpress such that it wouldn't even be the same piece of software, and 
you would have to solve the other Hard Problems above, but I think it is 
technically possible at this time. But in the general case, you might 
have more luck working towards a Singularity and then asking the 
Machine-Gods for an answer.

What seems more realistic to me is taking snapshots of a Web site and 
distributing those as files instead, rather than trying to distribute 
the actual Web site program. That's why we designed Mirror As You Link 
to work that way.

These are all the hard issues I can think of, as a technical person with 
some distributed systems background. There may be others, since in some 
cases we're really exploring uncharted waters here.
- Daniel Margo

On 02/02/2012 10:40 AM, Kendra Albert wrote:
> Some interesting stuff
>
> ---
> Kendra Albert
>
> Research Assistant to Jonathan Zittrain
> Berkman Center for Internet and Society
> Harvard University
>
> Forwarded message:
>
>> *From:* Jonathan Zittrain <zittrain at law.harvard.edu>
>> *To:* Rob Faris <rfaris at cyber.law.harvard.edu>
>> *Cc:* emstark at gmail.com, Kendra Albert 
>> <kalbert at cyber.law.harvard.edu>, Alicia Solow-Niederman (Google Docs) 
>> <asolowniederman at gmail.com>
>> *Date:* Wednesday, February 1, 2012 6:08:49 PM
>> *Subject:* Re: Fwd: [liberationtech] Concept for takedown-resistant 
>> publishing
>>
>> thanks
>>
>> At UTC-5 03:51 PM 2/1/2012, Rob Faris wrote:
>>> I have no idea if this has any merit - but think of you when I see 
>>> content mirroring.
>>>
>>>
>>> -------- Original Message --------
>>> Subject: [liberationtech] Concept for takedown-resistant publishing
>>> Date: Wed, 01 Feb 2012 21:49:42 +0100
>>> From: Fabio Pietrosanti (naif) <lists at infosecurity.ch> 
>>> <mailto:lists at infosecurity.ch>
>>> To: liberationtech at lists.stanford.edu 
>>> <mailto:liberationtech at lists.stanford.edu>
>>>
>>>
>>>
>>> Hi all,
>>>
>>> with a brainstorming with various persons it went out an idea of a
>>> concept of a takedown-resistat publishing system for website.
>>>
>>> I'm writing here to submit the concept idea to contribution/critics,
>>> maybe someone will do it someday (if feasible).
>>>
>>> I tried to abstract two concept:
>>>
>>> a) What is a website?
>>> A website is a set of information (text/images) that can be accessed by
>>> a user trough a web browser.
>>>
>>> b) What do you need to be takedown-resistant?
>>> Have a lot of mirrors, on as many server as possible around the globe.
>>>
>>> c) How do you make a lot of mirror available?
>>> By making use a very simple and diffused technology for the mirroring,
>>> possibly something that's already diffused across a lot of users.
>>>
>>> d) Which is the most known/used information distribution/mirroring
>>> system used nowday?
>>>
>>> Bittorrent P2P system.
>>> Bittorrent is the system that today is most used to do file-sharing,
>>> de-facto spreading, distributing, mirroring files.
>>> Bittorrent software is widely available and heavily diffused among
>>> users.
>>>
>>> So, if it would be possible to let a browser easily access the content
>>> available on bittorrent, it would be possible to easily create a
>>> scalable, distributed and resistant network of mirrors capable of
>>> resisting takedown.
>>>
>>> Obviously this require:
>>> - That the content on bittorrent should be file containing all the
>>> elements of the website glued together
>>> - That the web browser should have capability to access a such content
>>> on Bittorrent
>>>
>>> I am not entering into the technological discussion, if it's feasible or
>>> not feasible (maybe not, maybe yes).
>>>
>>> As a concept, what do you think? Other ideas/extensions?
>>>
>>> -naif
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