A global decentralized encrypted datastore with anonymous publishing

https://github.com/tarcieri/cryptosphere

by adulau • 14 years ago

329 201 14 years ago

github.com

mtrn2• 14 years ago

... in 410 lines of code.

judofyr• 14 years ago

Well, he's already built Celluloid (for handling concurrency) and DCell (for handling the distributed part).

mtrn2• 14 years ago

Just learned about those two projects, thanks.

bascule8• 14 years ago

Also this is the second p2p system I've tried to develop: https://github.com/tarcieri/distribustream

lucaspiller• 14 years ago

Should be noted that most of the documentation is theoretical. There isn't really much implemented yet, you can't yet use it.

bascule8• 14 years ago

For what it's worth, most of my time has gone into working on Celluloid, which is the concurrent object framework I'm using to write the Cryptosphere, as well as taking the rather intensive http://crypto-class.org

conductor3• 14 years ago

Tony Arcieri, be prepared for airport searches and harassing interrogations.

edit:

Well, at least that's what CryptoCat author has got

knowtheory4• 14 years ago

Depends how he plays it. The author of CryptoCat and also Jacob Applebaum (who works on TOR) have been outspoken in the media about their gear and its intent (and in Nadim Kobeissi's case, he's not an American citizen).

I'm betting that Tony could get away with keeping things on the downlow and not getting harassed too badly. But this is an empirical question. We shall see.

eleitl• 14 years ago

Small correction: it's Tor, not TOR.

pyre3• 14 years ago

I thought that Jacob Applebaum gets harassed due to his connections to Wikileaks. The Tor Project was US government-spawned after all (wasn't it a Navy project?).

Wilya• 14 years ago

People get searched and interrogated at borders all the time. That doesn't, by far, only happen to crypto guys.

So, you might as well give them a sensible reason to interrogate you :)

conductor3• 14 years ago

You should read the AMA of Nadim Kobeissi, Cryptocat author, on Reddit - http://reddit.com/r/IAmA/comments/x9q0a/im_nadim_kobeissi_cr...

Edit:

I wanted to post not the AMA, but this:

Cryptocat creator, Nadim Kobeissi, talks about his border interrogations - http://www.wired.com/threatlevel/2012/07/crypto-cat-encrypti...

> So, you might as well give them a sensible reason to interrogate you :)

They don't know who am I ;)

bascule8• 14 years ago

The project has enough legitimate uses I don't see the need to hide my identity.

muyuu• 14 years ago

I'd think so too, however I'd be too paranoid to publish this. Actually I haven't published a similar thing I made myself not too long ago.

s_henry_paulson• 14 years ago

Fantastic idea. What happens though if a peer sharing data goes offline? Does that person's data disappear as well?

Or can you build up enough "creds" to keep your data in the cloud for some time after your node disappears?

ewillbefull4• 14 years ago

Or can you build up enough "creds" to keep your data in the cloud for some time after your node disappears?

Bingo, from what I understand. More to the point, the data will persist as long as users continue to transfer it.

coob2• 14 years ago

How do I not unwittingly get CP being stored on my device?

StavrosK6• 14 years ago

You don't. Why?

lrem• 14 years ago

Maybe he actually cares about the children?

bmm6o• 14 years ago

Maybe he doesn't want to risk jail time. And that's not even supposing he doesn't want to aid the distribution of it.

valdiorn• 14 years ago

you get "something" stored on your device. You don't know if it's a students English paper, home made pornography, nuclear launch codes... or CP. You just get a block of bytes that sits on your drive, and maybe, somebody somewhere has the key to unlock it.

Until that happens, you don't know, you don't need to know, and you can't know, that's the whole point.

drcongo• 14 years ago

Pretty sure this makes it illegal in the UK under our crazy encryption laws [1]. I definitely wouldn't want to be the one to test it.

[1] http://news.ycombinator.com/item?id=4234614

__alexs• 14 years ago

This is the reason that there is no public Tahoe-LAFS network also. To run a node on a network like this you need to be brave, much braver than even operating a Tor exit node.

The addition of the long chain activity log may perhaps add some disincentive to upload CP in the first place but getting the economics of that (e.g. ease of getting upload privileges) right sounds like a difficult balance though.

soult• 14 years ago

As someone who ran the public facing node with web-interface for the public grid for a while, I can assure you that it is less concerning than running a Tor exit. You will know the IP address of everyone who downloads and uploads from you via the web-interface, and you won't know the data of those who only use your node for storage.

The only complaint I ever received was from Sony after those "Geohot revenge hacks", in which they claimed that a hacked user database from one of their services was copyrighted by them, while at the same time they denied that it actually was the real user database.

We did some searches for the URL of the webinterface and discovered that it indeed was mostly used by "Anonymous" as a Pastebin alternative, at which point it was decided that we did not want to aid in the spread of personal information, which is why it was shut down.[1]

So you are right, there is no public grid because of unwanted files, but not because of Child Porn, but because of some script kiddies.

1: http://article.gmane.org/gmane.comp.file-systems.tahoe.devel...

JulianMorrison2• 14 years ago

Going by the description, if you know a file's plaintext, you know both its plaintext hash (decryption key) and its encrypted hash (storage key). The communication to request files uses the storage key. It would be rather easy to identify by statistical means, people who request files of a common type, for example known CP images. Forwarding a few requests for CP or having it stored doesn't indicate anything. Reading or writing a lot of known CP would be probable cause for a search. This is especially easy because the majority of CP is not new and FBI presumably has the whole damn lot on a hard disk somewhere. They can easily pre-compute hashes and just sit monitoring.

As a result, this network would be useless for CP-mongers, they'd get caught about as easily as using plain old FTP.

On the other hand, I do think the ability to pre-compute hashes is a flaw that massively reduces this network's usefulness to dissidents. It is quite effective as a "publish a manifesto network" with a secret writer and overt readers - the original write is of a never-before-seen file, there is no hash to monitor. It's unsafe as a "store my pirated stuff" network, writers of a well known file can be tracked. And it would take very little statistical monitoring to reveal the interests of a reader.

maxerickson2• 14 years ago

It would be trivial for a user to layer some encryption on top of the service, preventing anyone on the network from doing any analysis of what they are transmitting.

amatus• 14 years ago

One could simply modify the known file in any way (say, appending garbage) to change the decryption key, ciphertext, and storage key.

knowtheory4• 14 years ago

However, in a direct peer-to-peer exchange the Cryptosphere does nothing to mask the transactions a particular is performing, as opposed to systems like Freenet and Tor which make an effort to obscure which host you're actually talking to by routing them through a chain of proxies. In this regard the anonymity guarantees of the Cryptosphere are no different from a system like BitTorrent, aside from the plausible deniability defense that comes from the fact all content is encrpyted and peers automatically provide storage service to other peers.

Instead, the Cryptosphere favors system robustness over guarantees on anonymity. Participants in the system maintain a history of their activities in the form of a long-chain certificate. You can think of this being somewhat like the BitCoin block chain, where the longest version always wins, and its integrity can be cryptographically verified. Every peer maintains its own long chain certificate of all its activities, including services requested and services completed.

Rather than verifying the integrity of a long chain based on hashes, the Cryptosphere uses public key cryptography. Peers requesting services sign off on both the request and delivery of a service (e.g. storing and serving a particular chunk of a file). While in isolation the data points contained within a particular long chain certificate are meaningless, peers can collect several of these certificates and build a database of other peers in the system, using tools like collaborative filtering to make intelligent decisions about which other peers are worth interacting with.

This is interesting. If i understand correctly, this means that given a transfer that you'd like to engage in, searching for a particular file you can trace back the provenance of that file through a network of peers who are making it available (if their transfer histories are accessible).

alttab2• 14 years ago

trace back the provenance of that file through a network of peers who are making it available

That doesn't sound very anonymous, does it?

knowtheory4• 14 years ago

I could misunderstand what the intent is.

If this is just a distributed block based storage without an index that folks can search, then it's more akin to a way for you to ask folks to hold on to encrypted data for you for a while (without them knowing what the encrypted data actually contains).

I think it's more of a matter of how secure the block chain is. Note this part of the opening blurb:

To ensure quality service and prevent abuse, the Cryptosphere uses an integrated cryptographically secure reputation system which provides a distributed web of trust.

ewillbefull4• 14 years ago

Instead, the Cryptosphere favors system robustness over guarantees on anonymity.

You trace back the "provenance of that file" through crytographic signatures. You could make your own throwaway identity, use it to publish something, and through the continued propagation of that data through the network its publication would no longer require your activity.

It should be considered psuedoanonymous publishing.

bascule8• 14 years ago

You can confirm any given peer is holding a particular portion of a file (sometimes called the "confirmation of file attack") however you can't prove they published it.

The peer "block chain" will only contain transfer metadata, not specifically which files are transfered. That information is only known by the peers involved in the exchange.

And that's where the anonymity of the system is definitely inferior to FreeNet: peers involved in any given exchange know exactly what was transferred and to what IP address.

I decided not to solve the anonymous transport problem because Tor, I2P etc are working quite diligently on that and it's a hard enough problem in and of itself. I think this has been a big stumbling block for FreeNet.

mtgx2• 14 years ago

Could this be used for https://projectmeshnet.org and how?

ewillbefull4• 14 years ago

cjdns doesn't need a bartering system for handling traffic. It uses Kademlia and some novel routing concepts, peering is assumed to be mutual because it's already explicit.

dedward• 14 years ago

Does this not set things up for a hash collision? They do exist, after all... if this scales to global proportions using SHA256 without verification for deduplication (if I read this correctly) is a risk.

ewillbefull4• 14 years ago

256 bit collisions are too improbable. The distributed hash table that BitTorrent uses relies on a 160 bit keyspace (SHA1) and that is seen as sufficient.

wcoenen• 14 years ago

Assuming that there are no weaknesses in SHA256, you'd have to calculate a set of 4.8x10^35 hashes to have a one in a million chance of seeing at least one collision in that set[1].

If you could calculate (and store!) a trillion trillion (10^24) hashes per second, that would take about 15000 years. Needless to say, nobody has ever found a SHA256 collision.

[1] http://en.wikipedia.org/wiki/Birthday_attack

bascule8• 14 years ago

There are 115792089237316195423570985008687907853269984665640564039457584007913129639936 possible SHA256 hashes, which is a few orders of magnitude away from the number of atoms in the observable universe. The chances of an accidental hash collision are vanishingly small.

peteretep• 14 years ago

I had half a design prepped that allowed a similar thing using bitcoin wallets - in order to buy space on the system, you have to have a bitcoin in a wallet, and use the comment on the commit of the bitcoin to the wallet to sign the piece of data...

api15• 14 years ago

Unfortunately it will end up full of kidporn just like Freenet. This says a lot about the present state humanity, and what it says isn't good. Giordano Bruno and the Renaissance alchemists would have killed for a system like this, but the most interesting thing we can think of to do with it is fill it full of pictures of child abuse so people can jack off to them.

It's nasty stuff, too. This is not "merely offensive." Kids are abducted and murdered to make this stuff. In some cases, the act of making it causes bodily harm. (Think of the mechanics of an adult having sex with a six year old.) In parts of the world children are more or less raised for the purpose. It's horrific. Picture someone getting off on photos of war atrocities. This is up there with that, but worse... imagine that the war was held expressly for the purpose of producing the images.

Edit: there is also, of course, rape porn depicting adults being abused horrifically. That isn't any better, and freenets are full of that sort of stuff too.

I'm not saying the technology is bad. I'm saying that it says something very depressing about the users of said technology. It also makes me dubious about running nodes on such networks, since I know that a lot of the material I'll be storing and forwarding is abuse-porn.

kvnn• 14 years ago

I want to solve this problem.

api15• 14 years ago

I've thought about solving this problem too.

One idea I've had is a content-type-restricted network that permits only text. That would allow utterly un-censorable communications: chat, planning revolutions, whatever, but wouldn't be useful for CP. (Unless you like ASCII-art CP.)

It could support ANSI. That would be neato. It would feel like the old BBS world. Wonder if anyone would still care if a name like ViSiON-X were stolen for it. :)

iand2• 14 years ago

I've thought about this many times. How can you create a system that preserves the anonymity of publishers in persecution situations but excludes the child pornographers? The difficulty comes down to the fact that there is no technical difference between the two classes of publisher, just a moral one. Suppose the persecuted wants to share pictures of children being abused by government forces?

One idea I had was for the system to be semi-anonymous. Publishers would form public groups and the publication of content comes from the group as a collective. The members of each group are known, but the specific originator of the content within the group is not. This is the spartacus model of anonymity :)

StavrosK6• 14 years ago

Oh wow. There's a discussion about an anonymity network being used for horrible stuff, and people say "I want to solve the problem and make a network that can't be used for horrible stuff"?

I want to stop people from doing horrific shit to other people in the first place. Unfortunately, I have no idea where to start...

david927• 14 years ago

What if you only connect to those you know? If you don't trust someone, don't connect to them. It causes other problems, but those are much more solvable.

*Edit: If Google can use reputation to solve search, why can't reputation be used to solve this?

crusso2• 14 years ago

I think that all you can do is to have some system of classification and rating validated by a web of trust reputation system.

As I evaluate content on the network, I classify it and rate it. My identity associated with those things is established though (possibly) anonymous. Over time, islands of trusts within the web will form that can be used to help filter large amounts of content.

If I start a node, I can link to islands of trust to only allow verified content acceptable to my filters to pass through my resources.

It's not perfect. Some will attempt to game the system by building up trust and then attempting to sneak content through. Some will attempt to hide illicit content in innocuous content.

utnick• 14 years ago

I think you would need to limit the scope from an entire decentralized , anonymous 'network' to just a decentralized anonymous website or discussion forum..

Something like an anonymous decentralized HN or reddit with mods that have the ability to ban posts, topics , & users. It wouldn't be as 'free' as tor or freenet, but with the right group of benevolent dictators it could be as free and useful for a certain niche topic like politics or news.

quadhome• 14 years ago

Probably not.

The non-repudiable tracing of exchanges make it easy to trace consumers of a piece of data.

See their note:

In this regard the anonymity guarantees of the Cryptosphere are no different from a system like BitTorrent, aside from the plausible deniability defense that comes from the fact all content is encrpyted and peers automatically provide storage service to other peers.

user495983• 14 years ago

...everyone knows child porn is bad. It's existence though, does not negate the usefulness of a system. Not that cryptosphere is going to be the open government revolution, but your comment is a useless vomit of emotional blather.

api15• 14 years ago

Okay, I'll re-state it technically:

How do we design a system that is anonymous and un-censorable where users can opt out of being relays for certain types of data?

Hard problem. Trying to solve it would be interesting. Not trying to solve it would make you identical to FreeNet and Tor and all the other efforts in this area, and thus less interesting.

I agree that there is no 100% solution to this problem, since all data can be converted to any format. There is also no 100% solution to pollution in a city, for example, or public health, or usability of a GUI. But there are 90% solutions that could make the problem marginal rather than severe.

BTW, on my "emotional vomit:"

Tell me. If these networks are for real human beings to engage in open communication, what happens when one of these real human beings comes across... say... a picture of a little girl being cooked over an open fire like a pig. (I didn't see this, but I was discussing the Tor .onion network on Reddit and someone claimed they came across this. I believe them.) Do you really think that person is going to return to this network to discuss... say... politics or economics or their local election?

It is a problem. To strip away the "emotional vomit," let's call it a usability problem. How do we make a freenet that is usable for non-psychopaths?

Edit: what I'm really saying is this:

Freenets have been done. It's a solved problem. Add some PK crypto and some hashing and some onion routing and shake.

What isn't a solved problem is: make a darknet/freenet that your mom would feel comfortable using. Make one that your average person -- maybe one with kids and thus really turned off by CP -- would want to one-click install from the Mac app store and browse.

THAT would make a serious political impact. Now you'd have hordes of average people using an utterly uncensorable chat system that was also hard to data-mine and tie to identity.

Right now, most people are going to start browsing the offerings that already exist (Tor is pretty easy to set up) and see stuff like "world's largest archive of hard-core lolita!", close the app, delete it, and never return. That's why these networks are not very popular, and it severely limits their political impact.

crusso2• 14 years ago

I disagree. I found his post to be very informative. I like the idea of an encrypted anonymous network precisely because I have this romantic notion of people of the world sharing important information with each other that can't be stopped or even tracked by governments or big corporations.

If the reality is that my contribution of resources to a project mostly just benefits a bunch of child-porn creators doing horrible things to innocent human beings, then I have to admit that my romantic notion is naive and behave correspondingly.

Sometimes you just can't have nice things because the worst members of society will criminally abuse them.

debacle• 14 years ago

I've seen some terrible things on 4chan posted by trolls or spammers. Sparing my morbid curiosity, how much worse does it get? Are any lines drawn?

api15• 14 years ago

Worse. Ask in Reddit /r/onions.

don_draper• 14 years ago

Why can't there be a text only system for people that don't want to look at images? You would think that would be possible.

themstheones• 14 years ago

What's to stop someone from storing a base 64 encoded image in a text field?

tomjen32• 14 years ago

CP will always exist. Especially if you group everybody under 18 into that category (a 17 year old is not a child, a six year old is) -- a 16 year old can't take nude pictures of herself without becoming one.

That Freenet is currently filled with it is a good thing -- it indicates how much pressure society puts on the people who are into this stuff and that no other group, such as the KKK, gun rights activists, astronomers, has that much reason to fear going public with what they right.

And any such group will quickly fill freenet up with other content, as it will be much bigger than the child abuse rings.

waterlesscloud2• 14 years ago

That's an interesting line of thought, but then where's that other sort of content from more repressive societies, of which are are many?

kragen• 14 years ago

Your comment about "quickly filling freenet up with other content" seems to assume that many more people are interested in astronomy, gun rights, or the KKK than are aroused by child pornography.

Is that true? How would you know? Is there statistical information out there about what fraction of the population is aroused by child pornography? Given your statement about naked 16-year-olds sexting falling into that category, it seems implausible.

dogprez• 14 years ago

I've taken some time to consider this issue myself. As other posters have noted its impossible to stop in a system where data is transmitted. I prefer living in a world with free communication (with a channel for criminals) than living in a world with restricted communication. The true crime here is child abuse, not the sharing of data. We don't say people aren't allowed to associate in person without a government minder because they might be swapping photos of child abuse.

SkyMarshal2• 14 years ago

>...they might be swapping photos of child abuse.

But in this case we know they are swapping pictures of child abuse, we just don't know who they are. The problem is the inverse.

AnIrishDuck2• 14 years ago

I see these kind of services in a similar light to safe deposit boxes at banks - where you also have near-complete anonymous storage. I doubt any bank manager is losing sleep because child pornographers could be using his service.

The biggest problem with this mindset is proportionality at the moment - bank safe deposit boxes have much more public awareness than these services, and have thus gained wider use (and acceptance).

alanfang• 14 years ago

Couldn't this be solved by having such a decentralized system only be text based and not allow images/video etc?

Tloewald2• 14 years ago

Cough. Usenet.

_pferreir_2• 14 years ago

So, since people can put kiddy porn on images, images shouldn't be allowed at all?

SkyMarshal2• 14 years ago

You would probably have to have some kind of flagging system built into the network, so that people could flag bits and pieces as childporn or whatever categories you provide. The client could be configured to refuse any data with user-selected flags.

Of course it would depend on the network not being taken over by a majority of childporn distributors and viewers, and the flagging system would need to be resistant to spoofing and manipulating.

Tribler is heading that way with anonymous metadata, iirc their roadmap.

wnight3• 14 years ago

What kind of anonymous and untraceable system do you imagine where the files are visible to be blocked by other nodes? I've spotted a small bug...

hippich2• 14 years ago

This is wrong attitude. There should be nothing in place to censor anything. And you as a user should censor whatever you do not wish to see. I agree that certain things might be shocking in real free world, but this do not grant you right to block anything from anybody. Just from yourself.

api15• 14 years ago

This is naive because it ignores the social dimension of technology. As I said in another reply: when most people see horrific hard-core CP or rape porn, they will close the program and delete it. End of story. They will also tell all their friends that darknets are only for pedophiles.

Then, when the government wants to ban darknets, nobody objects because everyone knows darknets are only for pedophiles because what non-pedophile would want to be immersed in kidporn?

This severely limits adoption and thus political impact. Average people are just not going to use it. Niche things do not change the world. Want to be really subversive? Build a darknet your mom would want to use.

montecarl• 14 years ago

Maybe this speaks pretty highly of the current level of free speech? Perhaps everyone, for the most part, is already able to say what they want and the number one use for systems like this are these horrible things and not say a newspaper that speaks out against the local government. I don't mean to say that a system that provides perfect free anonymous speech wouldn't be useful, but for every person who has something to contribute to wikileaks theres millions more who just want to get off to sick stuff.

gst• 14 years ago

And now replace the "Freenet" in your sentence with "Internet". The sentence is still valid. But would this be a reason to shutdown the Internet or to not run any Internet backbone routers?

kevindication• 14 years ago

You raise a good point. There is a difference, however; the Internet is actively monitored and ISPs respond to/work with the police to reduce this kind of content. Can the same be possible on something like Freenet?

api15• 14 years ago

I can browse the Internet for a long time before I see an archive full of hard-core pre-teen porn unless I go looking for it. It is difficult to browse the Tor .onion network without seeing at least links to this. Sometimes users land on it by mistake. Try it.

Tor gives the impression of being a sea of kidporn with little islands of interesting stuff, especially when you factor in the cognitive fact that human beings give greater weight to negative stimuli.

mtgx2• 14 years ago

Don't blame the tool. Never blame the tool. Knives can do horrific murders, but they are pretty useful for cooking as well. I'm surprised your comment is the top one here.

api15• 14 years ago

I'm not blaming the tool. I'm pointing out its inadequacy. I am saying there is an interesting and very hard problem here that severely limits the adoption of these technologies, and that solving it would be both interesting and important.

The darknet problem as defined by most techies is solved, yet almost nobody uses these systems. Why?

JabavuAdams2• 14 years ago

> Never blame the tool.

We can predict how a tool might be used by various users. We can also look at how similar tools have been used historically.

If, empirically, certain tools tend to be mis-used in familiar ways, it's just ignorant to say "don't blame the tool". It's a straw-man. When people "blame the tool", it's typically short-hand for arguing that the creators and distributors of the tool share some of the blame for its misuse, along with the abusers.

I.e. there's a long history of tool creators playing dumb / innocent about the predictable and likely abuses of the tools they create. There's an equally long history of these abuses, so any such arguments are to maintain cognitive dissonance, or made out of pure ignorance.

davidcuddeback• 14 years ago

> I'm surprised your comment is the top one here.

At least at the time of writing this, his comment is the only top-level comment. So it's not so much that it's the top-rated comment, but rather it's the only one that can be displayed in that position.

EDIT: Nevermind. I didn't notice that there are multiple pages of comments. Disregard.

thebigshane2• 14 years ago

Interesting. I think most people here on HN also believe in gun rights (as a fundamental right, not that they actually own a gun) and so the saying "Guns don't kill people, people kill people" probably goes over well here.

BUT don't most people here also wish that nuclear weapons could be un-invented? Isn't that the general feeling among those that participated in the development of that technology, that they wish they never did it?

What about the responsible disclosure of zero-days? Don't we agree that those are things we don't want floating around so that anybody can potentially use them before it can be patched?

Or what about an intentional backdoor into an encryption system? Is it only bad if people use it? Or is it bad in of itself?

It is obviously more complicated than "never blame the tool". Some knives are designed for cooking, some knives are designed to inflict maximum damage and pain to human flesh.

learc83• 14 years ago

What about a system that establishes a series of trusted agents, who get the data first, and have to approve it to propagate it onto the the wider publicly available network.

Anyone could become a trusted agent by publicly verifying their identity. Basically you need to find at least one other person who's identify is public to "sponsor" your information.

If you are publishing information the Chinese government you find a U.S. sponsor and vice versa.

burke• 14 years ago

I think it actually says a lot more about how generally-free our society is.

Giordano Bruno was imprisoned and executed for disagreeing with the church, so had much reason to hide his activities, even though they are what we could definitely consider "legitimate".

Child pornography producers and consumers are similarly persecuted, though clearly with much more sound reasons.

At least in western countries, there aren't a lot of instances of repressed communication that need to be conducted across a channel like this -- especially few legitimate ones. This is not to say that such a system isn't useful; just that I believe the fact they're so full of child pornography and the like is actually, in a roundabout way, an indicator of a healthy society.

endtime• 14 years ago

Your comment is about child porn, not about TFA. Please stay on topic.

thruflo• 14 years ago

Precisely -- I opened up the comments to see what people thought of the quality of the implementation. Does this guy know about cryptography and robust decentralisation? What are the trade offs in the architecture...?

_pferreir_2• 14 years ago

As others have said, guns don't kill people, other people (and Chuck Norris) do. Unfortunately, the right to privacy has this side-effect of allowing people to hide from others really nasty things. But it will always be like this: laws and rights protect both well and ill-behaving people. Giving those up would, however, harm all of us.

moondistance• 14 years ago

Couldn't it - or a similar algorithm - be used as a bittorrent alternative with superior anonymity? If yes, this might become a more common use case.

spullara• 14 years ago

Couldn't you require N random contributors to approve of each upload before it is published? With that in place, either the system is just a group of bad actors or the good actors weed out the bad content.

mgunes• 14 years ago

Accidentally downvoted you; I thought people on HN interested in autonomous, decentralized systems not acquainted with Giordano Bruno should become so:

http://en.wikipedia.org/wiki/Giordano_Bruno

http://warburg.sas.ac.uk/index.php?id=446

"The Art Of Memory" by Frances Yates outlines the pathway of mnemonic and knowledge systems from alchemy to the Rennaissance, and is a comprehensive introduction to the life and work of Giordano Bruno, Ramon Llull and many other ancestors of our various technologies of memory.

http://www.amazon.com/The-Art-Memory-Frances-Yates/dp/022695...

grandalf2• 14 years ago

Your argument is somewhat self-contradictory.

We know that lots of child porn exists. If you create additional scarcity by preventing the exchange of old/existing child porn (probably mostly 20 year old pictures, etc.) then you increase the chances of new children being exploited.

The legal adult industry has seen most of the profit evaporate b/c of the large amount of free content. The only people making money are those selling ads on top of existing content, which is often not even owned by the companies hosting it. The original owners lack the resources to enforce copyright law b/c they have no income stream to use to do so.

So rather than relying upon the idealistic notion that all exploitation and exploitative pornography can actually be successfully eliminated, it might make more sense to take a more pragmatic view about the forces of supply and demand involved, with the goal of reducing additional harm.

tobias3• 14 years ago

Exactly. Anyonymous payment however would be bad. And currently, with e.g. bitcoin scramblers, we are getting there.

I can see no harm in anonymous data exchange (except copyright infringement) on an open society. But if you can order whatever you want online anonymously -- that could result in some deplorable stuff. (That's why I think bitcoins will get shut down entirely by goverments at some point)

na852• 14 years ago

Sadly, that's the price you pay for free speech. The only way to ensure that the world's whistleblowers can publish what they want without fear of reprisal is to ensure that the world's child pornographers can also do so.

rhizome• 14 years ago

Consider the possibility that these networks are seeded with that content by those immune to prosecution for doing so, who also have an interest in that kind of freedom being curtailed. This is conspiratorial, and of course I have no evidence, but I simply don't think rapey kidporn is as popular as it's portrayed.

wnight3• 14 years ago

Strange, how you say someone could wage a social denial-of-service attack against Freenet with a bit of kiddy-porn FUD...

None of the links I follow into the onion (coding mostly) have ever led to porn, let alone CP. Even if it's everywhere you look (and maybe you should consider why that is) it's nowhere I and most other people look.

Even if there were a non-insignificant amount of CP being distributed there are really just two options, 1) there's a super-secure, secret group of pedophiles who cooperate to abduct and molest children and they continue to get away with it, or 2) various law enforcement groups use the same few pictures over and over in stings and honeypots.

No, it's a nigh-unto made-up problem, and to the tiny degree it may exist at all, it's exactly the same on the Internet as a whole, on Dropbox, via shortened URLs in twitter, etc.

To combat the problem perception that Tor is for CP problem simply quit telling people about it constantly. And if you're told that's all Tor is, treat it exactly like you would someone who started at the sleaziest portal they could and complained the internet was full of porn.

As for you knowing what Freenet is full of, that's impossible unless you're claiming to have seeded it.

rdl• 14 years ago

Maybe stick to a text-only format. Very little illegal text which isn't otherwise beneficial.

lizzard2• 14 years ago

This looks like the perfect platform for feminist activists to name and shame rapists. Great!

Zikes• 14 years ago

Doesn't the media do a pretty good job of that already?

sweis• 14 years ago

Is this thing using raw RSA with no padding? https://github.com/tarcieri/cryptosphere/blob/master/lib/cry...

bascule8• 14 years ago

Padding is added automatically by OpenSSL unless explicitly disabled. Also I will be switching to Curve25519 (for DH-style key exchange) and ECDSA (for signatures) quite soon. There will be no other use of pubkey crypto, so actually that entire file will be gone soon.

Torgo3• 14 years ago

I quickly read over the description of how this works. Nodes have a crypto identity which is used to establish trust between nodes, and storing data from another node gives you bandwidth "credit" to download other stuff. Transactions are cryptographically signed, but presumably this is safe because the contents of the files are unknown because they are encrypted. So how are they encrypted and then stored, and later retrieved? Content is hashed, the hash is used as the AES256 decryption key. Another hash is made of the encrypted data, and this is your lookup key. Only the crypto hash is needed to query a file, but it's useless to you unless you know the original data hash to serve as a decryption key.

I see two problems with this:

1. So, if both hashes of a file of illegal content becomes publicly known, like say on a website, I don't see how you avoid liability having it on your machine. It seems you can only avoid legal liability if someone stores stuff on your machine that is never intended to become publicly available. In any other case, the system has created a cryptographically provable trail between the data and your storage, which can be used to prosecute you.

2. The FBI can generate a SHA256 hash of every computer file of child pornography it has ever collected, and immediately be able to identify every node that contains this data. Presumably this gives them enough legal authority to shut down your node, regardless if you have plausible deniability that you are aware of the contents.

Torgo3• 14 years ago

I should mention, you change one bit of a file and it will obscure the file from the "FBI test". But still, you trivially can generate the Cryptoshphere lookup for any unencrypted file you have access to, and see if anybody has it.

bascule8• 14 years ago

Yes, this is known as the "confirmation of file attack" and there is no feasible way for the system to operate without it.

The confirmation of file attack is actually the degenerate case of the "learn the remaining information attack", in which the majority of the plaintext is known except for some low-entropy portion.

You can imagine a standard form letter that contains your credit card number. An attacker can then generate all possible permutations of that low entropy data and find matches where those are stored.

For more information see: https://tahoe-lafs.org/hacktahoelafs/drew_perttula.html

Torgo3• 14 years ago

Thanks for that information, that is extremely informative.

But what does this limitation mean for the security of Cryptosphere for its defined use cases? from the article: "If you want to store banned books or political pamphlets without attracting the attention of an oppressive government, or store pirated copies of music or movies without attracting the attention of copyright holders, then the confirmation-of-a-file attack is potentially a critical problem."

Doesn't this mean this system is DOA for its intended purposes?

lizzard2• 14 years ago

I think this may be a good solution for feminist hackers who want to name and shame rapists or incidences of sexual assault.

A global decentralized encrypted datastore with anonymous publishing

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