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Tor over Tor Hidden Services does not go in plaintext and it does not matter if exit nodes are being sniffed, because you never leave the Tor network.

That is SSL is not a problem for you, because the URL is self authenticating. This is especially useful if you have a newspaper, because you can print the address on the paper and not have to worry about CA and this kind of stuff.

Worth looking at is probably also GlobaLeaks (https://globaleaks.org/) that is a system that also uses Tor HS. This system is more actively developed and is designed to be extendable.

We are also happy to say that just last week we released the 0.2 release of GlobaLeaks. You can see a live demo on our site: https://globaleaks.org/.

Well, the government can connect the onion URI to the new yorker. Would it be feasible to use domestic warrants to identify the server? I'm not sure as to what end as it would still be end-to-end encrypted.

That's fine, the anonymity works both ways. You can't access an .onion without using tor, and in this way, use of tor prevents the .onion service from knowing who you are.

Contrast The Silk Road, where the .onion is being used primarily to protect the identity of the service itself (as most of the users give their physical addresses to the service).

Both are hidden services. One is privacy for the client, one is privacy for the server.

On the other hand, the page telling you what the Hidden Service URL is does go across the Internet as plaintext and can be modified to contain a malicious URL by exit nodes if you view it via Tor, which you'd probably want to.

If you are relying on Tor exit nodes being trustworthy, then you are using Tor incorrectly. All Tor does is anonymize your traffic, it makes no guarantees once it leaves the network.

Either make sure you are using end-to-end encryption or only use Tor for information you don't mind being public.

My premise is that based on the data I'm submitting, it might be possible to deduce my identity.

And it's certainly easy for trained government agents to to trick me into releasing too much information about myself when they pose as New Yorker reporters based on the information I just sent them.

If I'm submitting my data to the government posing as the New Yorker I'm exposing myself to much more risk than if I'm submitting my data to the New Yorker, provided I trust them. That's why I'm insisting on that onion link being displayed on a page that's EV signed. Because right now I have no guarantee that their http://tnysbtbxsf356hiy.onion link is actually the address of their drop box and not the honeypot the government has set up and put on a fake New Yorker page which they MITMd me.

But that's not an exit node. Yes, any .onion address that you don't personally verify[1] could be something other than it seems. In fact, with sufficient resources, that onion link could be rewritten in transit once it hits the backbone or your last mile provider. How would we know if it's arsta8rst87ars.onion[2] vs. dndspjsnbshsdrsts.onion?

[1] And even then...

[2] Yes, Colemak

Apparently it can't be rewritten, the address itself is a hash to a server key. That's why it's gibberish and not newyorkerdrop.onion

That's not what I mean.

On that page (http://www.newyorker.com/strongbox/, no SSL, no hashing, etc.) is an onion link. I see it as http://tnysbtbxsf356hiy.onion.

An adversary with sufficient access (whether to the server, or to the network between the New Yorker site and your browser) can rewrite that link without your ever knowing. Then you are legitimately directing your browser, once on Tor, to a spoofed site.

True, but you can bookmark it, and compare it against the one used by others. They're also short - you can write them down and communicate them offline.

To compare, ssh uses no PKI, but is relatively resistant to MITM as it stores public key fingerprints for a given service on first access.

bookmark...others...offline. Be more paranoid.

Yes, what if someone MiTM's your offline communication... /s

If the Feds (or whoever) were swapping out this address at a large scale, then the NYTs would notice and communicate to the public that this was happening. If the NYT was muzzled and every computer that you or anyone you know has it's connection being tampered with, then you are basically fucked anyway and this is the least of your concerns. At this level of paranoia you shouldn't be trusting the NYT anyway...

If they are not MiTM'ing this at a large scale, then quick verifications on other networks with other peoples' computers will work just fine.

Let's take a simple example. A soldier deployed overseas sees this link, sets up Tor, and sends some confidential information that includes evidence that the US government is up to some shenanigans.

After Manning and some other fun, the military is not really a fan of this happening, but realizes that it would provide an excellent way to identify seditious elements who don't have other channels to work out their moral dilemmas (or just their annoyance at being an expendable cog in the bureaucracy).

MilInTheMiddle proxy rewrites the page, replaces just that link with one that is under their control, then waits. People outside the military see the normal link, but a kid in Iraqistan sees the honeypot. When s/he sends secrets to the New Yorker (it's not even the NYT), the operator has a lead not only on what information may be flowing to the media, but is able to stop it and investigate the sender.

The same case could be made for financial institutions, government agencies, people in foreign countries with national firewalls, etc.

The only reason I'm not particularly concerned about this is that I strongly suspect that a) the organizations don't really have their sh*t together enough to do this in a fashion that wouldn't create immense blowback when (not if) discovered, and b) there are easier methods to get similar information already in place.

That scenario is what "offline" is for. That soldier could call up his mum and ask her to read off the link over the phone. There is no way that anything but an utterly game-changing surveillance and censorship system is going to MiTM that in time. Or he could give some local kid a candy bar to look it up at an internet cafe, or hold onto the data until more alternative communication channels open up for him. If this soldier's communication is blacked out to the point that he cannot ask anyone else to verify the link using an internet connection other than his own, then it probably isn't safe for him to be attempting whatever it is that he is doing in the first place.

It's not blacked out. It's subtly and near-undetectably changed. Who says the soldier is tech-savvy enough to know to talk on an alternate secure backchannel because s/he can't trust the same Internet that has fantasy football and funny videos on YouTube?

Let's reduce this even further. The New Yorker has put up a webpage saying,"Send your secrets here!" Pretend they put up a phone number instead. 1-800-231-2142. The military phone switching system can either automatically redirect calls to that number to a switchboard of impersonators, or they could change the number to one they already have, so that they can also capture military assets using personal phones, mobiles, etc.

The New Yorker page does not give any information about "offline" validation. They give a pointer to a supposedly secure dropbox. That dropbox may actually be secure, but there are a number of ways to subvert it.

Any information that they gave about offline validation could just be stripped out though! What exactly are you proposing that they do that could not be subverted by the very things you are concerned about?

Offline verification would work, but if we are assuming extensive MiTMing and meatspace impersonation then offline verification is just something the whistleblower needs to figure out themselves.

You're extrapolating things I haven't said. It is well known that signal interception (and communications interception in general) has been a tool used by the military and the government for as long as any of the above have existed.[1]

"offline verification is just something the whistleblower needs to figure out themselves."

You are seeing the point, albeit as if through a glass, darkly. The New Yorker has not advised anyone of this need, nor have they communicated the additional safeguards one much take, proportional to the risk of interception and identification.

[1] http://en.wikipedia.org/wiki/ECHELON, https://www.eff.org/cases/nsa-multi-district-litigation, black ops, http://en.wikipedia.org/wiki/File:Aldrich_Ames_mailbox.jpg, http://web.archive.org/web/20060210092316/http://www.liberty..., http://books.google.com/books?id=mAR0GI5ggf8C&pg=PA62#v=..., http://www.archives.gov/research/holocaust/finding-aid/civil..., http://www.britannica.com/EBchecked/topic/635080/Sir-Francis..., &c.

In cases where offline communication would catch tampering, why would the New Yorker's advisement to use offline communication go through untampered?

You seem to be misunderstanding me. I think that there is value to offline communication with trusted but unanticipated 3rd parties, but I do not think that there is value to the New Yorker pointing this out.

If the whole thing is legit and they made a page about it, they should notice when they lose control over how that page is displayed in various locations. It could be acceptance tested via many proxies. Maybe a counter-interference phishing bot could send emails and fills forms to make sure they go through correctly. Self-safety audits like that could be built into Tor itself so that these "red blood cell"-like bots are themselves distributed processes (maybe only as pre-installed plugins in the full featured Tor browsers).

Unless the Tor site is a honeypot. Hmm a bit odd they don't have any offline validation instructions on there ;)

I guess the downloaded source code could always be diffed with a known legit copy, if it was compiled on a trusted machine.

By the way, how does one determine the right amount of paranoia?

The first response to this thread helped me understand the issues better: http://www.wilderssecurity.com/showthread.php?t=228869

If we assume the adversary controls all network traffic as well as all Tor exit nodes but the would-be whistleblowers and the New Yorker's systems are out of bounds, a valid solution is still possible:

- The plainly accessible page needs to be served through HTTPS, preferably secured with an EV-SSL cert. The adversary would then be unable to read or change any of the site's content; i.e. the whistleblower receives the correct onion link.

- The onion site, too, needs to be served through HTTPS. All traffic passing through Tor is encrypted and thus out of reach of the adversary; traffic leaving Tor for the destination site is encrypted yet again and out of reach as well.

Since few CAs would accept to sign certificates for a .onion domain, that site might have to use a self-signed certificate. This solution remains secure for as long as that certificate's fingerprint is posted on the first page and the whistleblower cross-checks the expected and actual fingerprint values.

This should provide reasonable security for the exchanged message contents. In all likelihood, though, the adversary would be able to prove the whistleblower did communicate with the New Yorker.

One high-risk aspect of this whole deal is a possible breach at any of the whistleblower's trusted CAs. Convergence would be of some help there -- assuming the notaries involved are behaving correctly.

*edit: Sorry, I had a bit of a brain fart right there. Traffic to and from the hidden service (the .onion domain) never leave the Tor network and thus remain secure. Skip the second bullet point.

I get what you are saying, but that issue has almost nothing to do with Tor. Tor doesn't ensure the secrecy of your content, it only attempts to hide its origin.

If you don't trust the recipient then it doesn't matter if Tor is run by the government or not.

You could put on a disguise and use an open wifi access point in a city you've never been to before and bounce through 50 levels of proxy at the same time. If you tell the other person your name, it's not the technologies fault that you're no longer anonymous.

Bingo. Or you send documents that are traceable to a small group of people, including you, and everyone else has protection and/or an alibi. General, General, Colonel, Colonel, Short Bird, Corporal...wait a second.

My premise is that based on the data I'm submitting, it might be possible to deduce my identity.

I think the goal of Strongbox is to protect sources in the event that the New Yorker is forced to turn over material to the government. What they never knew, they can't turn over, but that doesn't apply to the information you leak. The government will be able to get at that information because writers will have to keep it for reference while they're writing and fact-checking their articles.

> How can you be sure that the data you are submitting is not intercepted? How can I be sure that all my traffic is not running through one government network (because all tor nodes still left are compromised)? How can I be sure that I'm actually submitting my information to the New Yorker in this case as opposed to a government server posing as them?

even if this were the case, how could you be personally identified? worst case is the government gets the document you meant for the new yorker, but you still wouldn't be identifiable (unless your name was on the document etc.). Unless you're saying the government runs the majority of tor nodes so they could track back to your ip?

Your confusing the issues of anonymization and eavesdropping. Tor exit nodes can eavesdrop on unencrypted Tor traffic, so you should always use end-to-end encryption if that is a concern. Tor Hidden Services don't need SSL because the protocol is end-to-end encrypted. Authentication is provided by the onion address itself, which is a fingerprint of the server's key.

Their website says that their hidden service is available at http://tnysbtbxsf356hiy.onion. But how do I know that I am on their website? How do I know it's not the compromised tor exit node that's serving me a modified New Yorker page that is just pretending that the hidden service is at http://tnysbtbxsf356hiy.onion when in fact it is at http://tnysbtbxsf356hjy.onion

The data I'm sending can be a huge give-away of my identity - especially if they play along, pretending to be the new yorker and then tricking me into releasing more information than I wanted.

If that page that's linking to the hidden service was served over SSL with an EV certificate, then I could be sure that the link isn't faked. Of course the New Yorker could still be compromised by the government, but as long as I'm willing to trust them, I can at least be sure that I just submitted my data to them and not somebody pretending to be them.

Someone mentioned this somewhere else, but the beauty for print news organizations is that they can print the address physically in their paper.

If that page that's linking to the hidden service was served over SSL with an EV certificate, then I could be sure that the link isn't faked. Of course the New Yorker could still be compromised

The New Yorker or any CA capable of issuing EV certificates present in your browser. Do you trust all of them?

Hopefully not, given that just yesterday there was a post on how the Saudis were planning on using CAs as an attack vector...

Good point. At some point, you'll need to communicate the onion address over a trusted channel. If you trust SSL, then you can serve the landing page over HTTPS, or as others have suggested, you could print the address in the New Yorker itself. I have also heard of using Namecoin or other proof of work schemes, although that would be outside the reach of the average user.

If neither of these avenues satisfy, a simple idea for defense-in-depth I've thought of is using .onion vanity name generators (see https://github.com/katmagic/Shallot) as a very simple proof of work scheme. For example, silk road's .onion starts with silkroad. Finding such an .onion address for a given private key requires brute force computation - according to the Shallot github, about 25 days. Therefore, generating an .onion with a recognizable string at the beginning makes generating a suitable address for spoofing that much harder. Of course, this is hardly a solution - big scary Tor-style adversaries certainly have more computing power than you - but it is something to consider.

> How can you be sure that the data you are submitting is not intercepted?

Tor is not meant to guarantee that your messages are not being intercepted. It is simply not meant to protect against this. Use end-to-end encryption. (Does strongbox use encryption on top of tor? I am not sure).

> How can I be sure that all my traffic is not running through one government network (because all tor nodes still left are compromised)?

That is the more pertinent question, indeed. That's the correct question about Tor security, and would be what woudl cause Tor to fail at what it does intend to do. There are some written analyses of this risk.

> How can I be sure that I'm actually submitting my information to the New Yorker in this case as opposed to a government server posing as them?

Tor isn't necceasrily meant to guarantee that either, an SSL cert with a known/trusted fingerprint would be. But you're right the new yorker is not doing the right things here either.

I am less worried about the integrity of Tor, but I think you are right that the new yorker is not doing all the right things to maximize security/anonymity here. Security is hard. But among other things, they ought to be serving all strongbox related things (including the endpoint you access over Tor) over https, and publishing their SSL cert fingerprint in multiple places all over the net.

> How can you be sure that the data you are submitting is not intercepted?

HTTPS

Hidden services can't / don't need HTTPS because they never leave the Tor network and are authenticated by the URL itslef.

Yep, I'm aware of that. He was specifically referring to exit nodes.

It would be nice if some of the companies who control a lot of bandwidth would dedicate even a few Gbps to the cause. Google comes to mind, it's in their interest for Tor to be fast and secure so that users in countries with internet restrictions can use Google (China/Iran/Syria all come to mind).

The problem with any one company controlling a large portion of the Tor network is that it would open up the network to a few new classes of attacks.

Multiple companies have the bandwidth.

I wonder though, would anybody actually use evidence gathered from Tor in that manner? That would mean revealing that they can feasibly do it and they'd lose a huge intelligence asset.

They'd get to see the information, but they wouldn't be able to action it without showing their hand.

I'm sure they have channels for information laundering. Example: they present the Tor evidence to one of their classified courts, get a sealed warrant to wiretap your house, and then re-collect the information from a bug they plant directly on your computer. Or they could just watch you closely until you screw up. Or they could honeypot you.

> Then again, maybe I'm just a paranoid coward. I'm so glad I don't have access to information anybody would be interested in.

I agree with everything else you're saying, but I should just point out one thing:

It doesn't matter whether or not anybody is interested in your information - especially in this era of en-masse passive data collection, you have the right to your own data, which includes the right not to be snooped on by third parties (governmental or otherwise).

It doesn't matter whether or not you "have anything to hide", only whether you have anything you want [voluntarily] to show.

</rant>

I think "privacy as a right" is a difficult issue.

I am down with "not getting tortured" as a right. But privacy is ... a privative. I think a more useful and fruitful direction will be requiring publication of holding of private data, and then we can enforce any number of outcomes.

Honestly, it's great that you're passionate about the issue, but that doesn't a logical argument make. Privacy is an intuitive concept, but it translates surprisingly poorly to reality. That's not to say privacy doesn't exist or isn't important, but that we don't actually know what it is.

Intuition makes for bad law, not least because everyone has different intuitions; it's basically asking, "Why don't programmers just program in English?"

Thankfully, my kids are learning Lisp before English, so at least that let them program more intuitively.

(Kidding: ... if only I could. My son doesn't seem interested in it.)

Do we actually have the right to our own data in America? Or are you just saying we should have the right?

It depends on whether you want someone to grant you rights, in which case, they're privileges.

I think you're misreading. "I don't have access to information anybody would be interested in" doesn't mean "I have nothing to hide." It means "I have nothing to leak."

I agree with the general statement, though.

> the onion URL given isn't using ssl either

doesn't need that hacky ssl stuff, it's end-to-end encrypted within the tor network. http://security.stackexchange.com/questions/11727/does-tor-h...

they could print the onion url in their newspaper even, if you don't trust your connection to the announcement. But yeah at sone point there is always some trust involved.

As a Tor Exit Node Operator, I can say that not all of the nodes are compromised.