AT&T Labs Backs Publius, A Freenet-Like System

joseph writes: "This article on C|Net announces Publius, a system similar to Freenet, meant to battle censorship on the Internet. What makes this approach interesting is its backing from AT&T Labs. Of particular interest in the article are the safeguards against the common opposition to such projects, like their use for piracy. Publius features no search utility and a maximum file size of 100k."

Comments

Inaccurate portrayal of freenet

[FreeUser]

No, it is not useless. It is designed for people with a REAL reason for being anonymous, yet wanting to spread information. For example, whistlerblowers, or people in countries with a less than perfect track record of censorship.

Except that, without the ability to do searches, no one will be able to find the material in question. Giving out the precise key is tantamount to publishing, so anonymity is preserved at one level, but possibly compromised at another.

Furthermore, whistleblowers and the like often need audio-visual proof of what has happened, such as audio recordings (ideally compressed with ogg or mp3 format for space), images, and even video footage. How is one going to reasonably publish that kind of important evidence of wrongdoing with a 100K filesize limit? By breaking up the files into 100K chunks? Then why not get rid of that limit to begin with.

It is not designed for pirates who want their MP3's (go to freenet for that sort of stuff).

This is a very unfair characterization of freenet and downright slandorous.

Freenet is intended to do precisely the same thing as publius, with the exception that freenet make no judgement whatsoever about content. Publius may make use of some better algorithms, but has also clearly made policy choices which make it less than ideal for dissidents to skirt censorship (such as the lack of searchability and the filesize limit, and worse: a philosophy of passing judgement on material and what is "fit" to be protected from censorship and what is not, with who deciding such criteria an open question). FreeNet can always adopt better encryption and storage approaches now or in the future, without making the same kinds of misguided compromises.

FreeNet remains IMHO the most promising approach to thwarting censorship of all kinds, today and in the future.

No search?

[FascDot Killed My Pr]

AT&T also started funding my BlackHoleNet project. See, what you do is you send a file (less than 100K, so break that MP3's into 100 files!) and BlackHoleNet sends it to a special device (/dev/null). Later, when you want to get a file out it is retrieved from a different special device (/dev/random). The only remaining bug in my system is that the process of traversing the wormhole from /dev/null to /dev/random is somehow scrambling the files. I just need some funding to get over this last hurdle.
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Let's not forget...

[mav[LAG]]

...that the most subversive file extension in the world is not MP3, or JPG or DivX. It's TXT - the plain old written word in electronic format. Ma Bell's service may be useless for exchanging large files but it could well be a very useful service for anyone who wants to be published and can't right now for whatever reason.

It's all in the words folks. The Chinese Government doesn't give a toss about its citizens downloading MP3s. It *does* care a lot about what they read...

limits

[Hobbex]

Limiting the file size to 100kB will drastically hurt this systems ability to support the freedom of speech. Unlike the days of the original Publius and the Federalist papers, not all speech today is, or can be, in the form of text.

Next time Will Smith gets a video of the NSA killing a Senator he will be able to upload it to Freenet. Will he be able to place it on Publius?

Does it say something about the sick influence of money in our world that they are willing to tolerate the usage of the system by child pornographers, but not by people who don't feel like giving money to the RIAA?

Re:Interesting cryptography

[Hobbex]

It's called an Information Dispersal Algorithm, or IDA.

See: http://www.acm.org/pubs/citations/journals/jacm/19 89-36-2/p335-rabin/

Interesting cryptography

[stuyman]

If you go to the actual Publius site you'll see the information on how the system works. It kind of reminds me of steanography, in that technically all the servers appear to have is random data. The difference is the key retrieval method.

The publisher takes the key, K that is used to encrypt the file and splits it into n shares, such that any k of them can reproduce the original K, but k-1 give no hints as to the key. Each server receives the encrypted Publius content and one of the shares. At this point, the server has no idea what it is hosting -- it simply stores some random looking data. To browse content, a retriever must get the encrypted Publius content from some server and k of the shares. Mechanisms are in place to detect if the content has been tampered with. The publishing process produces a special URL that is used to recover the data and the shares.

I'm wondering just how that cryptography is implemented, whereby having less than n of n shares still permits us to read the document. The pdf on their site seems to involve MD5 hashes in the process, but I was wondering if someone more cryptographically inclined could elaborate. Of mathematical note, they generate d*ln(d) shares, where d is the number of servers. This has something to do with the coupon collector problem, and that if you check d*ln(d) servers you get to every "unique" server.

All in all it seems a really good system; hopefully the common carrier concept will be better applied. Since the pages can be retrieved with special (CGI based I think) URLs, they could probably be indexed by standart search engines such as Google. I hope this works out

Re:Where is the benefit?

[MostlyHarmless]

I suspect that they did so for precisely that reason: To keep out mp3s. The system was designed to be a safeguard for free speech; if someone wanted to speak out against $CAUSE then he could do so without fear of retribution by (corporation, government, cia, pick one). There already is a perfectly good system (several in fact) for trading mp3s, so these guys wanted to focus on issues that, dare I suggest it, matter more in life than music.

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