Subrosa – An encrypted communication platform
subrosa.io
subrosa.io
These statements are mutually exclusive:
End to end encrypted: Nobody, not even us, can read or listen into your conversations.
Works everywhere: Visit subrosa.io from any computer. No download or install needed.
For example, he talks about the chicken and egg problem of delivering javascript over an insecure connection and then solves it later with SSL/TLS (but he doesn't acknowledge that this is a valid solution). Furthermore, we're all harping on javascript when you can't download PuTTY over an SSL connection.
He talks about browser cache but says that javascript can't control it. That doesn't mean it can't be controlled (see MANIFEST file).
I could go on, but the point is made, there are answers to the problems raised in the article. They may not be _easy_ (as the article complains some things are complex), but it's security on wildly complex systems...of course it's hard.
a) The chicken and egg problem of delivering javascript:
I am far from being good at this stuff, but I am confident that, given the opportunity if you deliver .js (or anything else) over an insecure connection, I can modify the content before it ever reaches the user.
As you and the article state, you could solve this problem by delivering the .js file with SSL/TLS. But, if you do this, I presume that you would need to encrypt every single resource on the page. And, if you have already gone that far, what would you gain by implementing browser based crypto when you have already solved the problem?
It strikes me that SSL/TLS are old enough to be well tested and researched, whereas if I wake up some morning and decide to implement my own crypto, I'm going to f* something up. I'd rather let smarter people do the heavy lifting.
But, I don't know what I don't know. What don't I know?
Furthermore, we're all harping on javascript when you can't download PuTTY over an SSL connection.
Please correct me if I am wrong, but if you can download PuTTY via an insecure connection, an attacker can just as trivially swap out the real version of PuTTY with a compromised version. That sounds really dangerous, but isn't that why the PuTTY developers add RSA/DSA signatures to their downloads page?
I would argue that if someone is smart enough to find a collision in both RSA and DSA, they can likely find easier ways to attack me than to swap out the real version of PuTTY with a compromised version.
What am I missing? disregard this question because I missed something very important - see my edit below
He talks about browser cache but says that javascript can't control it. That doesn't mean it can't be controlled (see MANIFEST file).
Thank you for this - I need to do some more reading. Though, wouldn't you get into the same problem where, unless you can control every single resource on the page (ie - serve it encrypted and make sure there are no XSS vulnerabilities) you can't guarantee that the browser is using the correct code? Then, doesn't that get back to the chicken and egg problem where if you're already implementing encryption, you don't need crypto in the browser?
--
Some of the ideas on that page (ie - the inability to generate strong random numbers) are kind of outdated. I believe that Opera uses a cryptographically secure Math.Random(). And, I think that there is an API to accomplish this in other browsers. window.crypto.GetRandom or something?
However, I still see all kinds of traffic with old versions of Internet Explorer (sorry to pick on IE). Wouldn't solving the crypto in a browser problem reliably require making everyone update to a modern browser?
I hope that I'm not coming across as being difficult, but I would love to learn and would appreciate any help you would provide.
Edited -- jimktrains2 wrote:
But those sigs are also coming over a non-ssl connection:-p
There goes my entire RSA/DSA argument! What a great thread...
This is indeed the point made by Matasano, but I don't think it's valid. Sometimes you want to segment the trust, or maybe your software provider doesn't even want to be in the data storage game. So I might trust one entity to provide me with software to manage my inbox, particularly if I can inspect that software at will, and have seen it pass through a security review, however I might not want to trust them with actually storing the contents of my inbox. In that case, it's nice to be able to encrypt the inbox (and the index, to allow for nice searching) in my browser, and then actually store them on a commodity storage provider (s3 or dropbox). And yes, I'd use modern web standards to give the user control over when a new version was downloaded too.
So, I need to get the software over SSL, and be able to verify within reason that it does what it is supposed to, and then use that trusted software to work with data which I can store on untrusted services.
This shouldn't matter, and would just provide a false sense of security. You ought to be verifying the signature of any program you're installing before you use it. Since you're running Windows the point is probably moot, but it is possible to install software reasonably securely.
Honestly, whenever you download anything, evne over SSL, you're essentially trusting that the remote computer is not only who you think the computer is, but the person you expect to be controlling it is the only person controlling it.
Out-of-band communication built out-of in-person trust are really the only way around that (i.e. trusting someone who trusts the PuTTY devs and gets you the hash/sig).
http://noncombatant.org/2014/03/03/downloading-software-safe... http://noncombatant.org/2014/03/05/followup-to-downloading-s...
This is offered with respect and not a desire to nitpick. I hope it doesn't come across as annoying :)
People with important information to communicate that they must protect from the powers that be (quite possibly to protect their own lives) will seek out secure methods; at the same time, the powers they're avoiding will be targeting secure communication methods.
I take fairly strong precautions with my keys: offline storage, encrypted, signing on an air-gapped machine. I'd bet you money that most people aren't so careful. There are probably a lot of secret signing keys sitting in DropBox.
These statements are mutually exclusive: End to end encrypted: Nobody, not even us, can read or listen into your conversations. Works everywhere: Visit subrosa.io from any computer. No download or install needed.
If you don't run your own server, the site's claim that "nobody, not even us, can read or listen into your conversations" doesn't apply to you.
There's nobody to whom both claims apply at the same time!
The developers might well be thinking along the lines that you describe, but I don't think that a visitor to the site is likely to understand the threats that way.
Edit: Looking at https://subrosa.io/security I think it's even more clear that they're making these claims for their own hosted instance of their software -- and that's what people here are most skeptical of.
Subrosa's value proposition is more as a meeting place then as a "secure" chat software.
This cannot possibly be true, given they are the root of trust for establishing the recipient's authentic public key.
Also, minified javascript really does not count as a source code release.
And it wouldn't take a complicated tweak at all to sneak the real password (or some sufficient version of it) back to the server, after which point certainly "even us" can read & listen in to all of that user's conversations.
I don't know much about WebRTC, but I think it's something you can set and Subrosa should be doing so in app-webrtc.js.
At first I thought it was an extra layer of security , like most online games have, to discourage username/password bruteforcing. (It's an obscurity layer, but obscurity layers are not by definition bad.) But you need to tell others your username to communicate with them.
They keep repeating they've been audited but not naming the auditors.
A system bragging about security leaving a known, patched hole like this open isn't a great sign.
- There is no demo, i can only guess that this is a "browser-based skype". I hate when i can't try it but it's free.
- Open-source, but no git repo?
Btw I had the same idea before (I posted it to an Idea Sunday thread) but I dropped the idea because i realized that no one needs this level of security, NSA is not interested in your chat with family and friends...
"Open-source, but no git repo" -- Open-source does not always entail git or Github.
"I dropped the idea because i realized that no one needs this level of security, NSA is not interested in your chat with family and friends..." -- I'm glad you dropped the idea because someone who doesn't understand why privacy is important shouldn't be making privacy applications. The NSA doesn't care about your chat with family and friends, until suddenly they DO start caring and everything you've said can be manipulated and transformed against you, whether your conversations were innocent or not.
Also as I understood, you don't have Facebook, Twitter, Skype, Googe, Outlook, YouTube, and even HN account because NSA could one day transform everything against you?!
Well, the NSA gave them a tip.
Now imagine you're running for public office and your opponents will pay top dollar for dirt on you. Imagine that one day you're at odds with your government and they'll use every piece of information they can to prosecute you.
Privacy from one's government and those who control/buy into it is something that nobody needs until they do.
That doesn't mean you can't have a public life as well. But why give out more than you need to?
Perhaps, a better scenario is that you are chatting with a fellow entrepreneur about bitcoin, a short while later they are charged by the IRS for tax evasion. Meanwhile, your conversation with them on the subject is discovered through the NSA machinery and is used to kick off an investigation against you.
I wish I had a better example, as that would serve us well to educate folks on the value of privacy. I'm writing in part that someone has a better example to share.
When not citing technology-focused issues, I like to use the bathroom example: "Would you use a public bathroom with glass walls?" It illustrates the difference between covering up wrongdoing and need for personal privacy, two entirely different things.
The idea of having a secure communication channel doesn't mean that ALL your communications have to be over secure channels, that would be ridiculous. Having the option to bank on a secure channel for conversations you deem private is a perfectly reasonable compromise. People in government agencies switch between insecure and secure mediums regularly.
Having a FB/Twitter/Skype/HN account just means that I am willing to make a tradeoff of privacy to use these services, one that I am okay with. This does not completely exclude me from occasionally using a secure medium, right?